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Leroux AE, Biondi RM. The choreography of protein kinase PDK1 and its diverse substrate dance partners. Biochem J 2023; 480:1503-1532. [PMID: 37792325 DOI: 10.1042/bcj20220396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 10/05/2023]
Abstract
The protein kinase PDK1 phosphorylates at least 24 distinct substrates, all of which belong to the AGC protein kinase group. Some substrates, such as conventional PKCs, undergo phosphorylation by PDK1 during their synthesis and subsequently get activated by DAG and Calcium. On the other hand, other substrates, including members of the Akt/PKB, S6K, SGK, and RSK families, undergo phosphorylation and activation downstream of PI3-kinase signaling. This review presents two accepted molecular mechanisms that determine the precise and timely phosphorylation of different substrates by PDK1. The first mechanism involves the colocalization of PDK1 with Akt/PKB in the presence of PIP3. The second mechanism involves the regulated docking interaction between the hydrophobic motif (HM) of substrates and the PIF-pocket of PDK1. This interaction, in trans, is equivalent to the molecular mechanism that governs the activity of AGC kinases through their HMs intramolecularly. PDK1 has been instrumental in illustrating the bi-directional allosteric communication between the PIF-pocket and the ATP-binding site and the potential of the system for drug discovery. PDK1's interaction with substrates is not solely regulated by the substrates themselves. Recent research indicates that full-length PDK1 can adopt various conformations based on the positioning of the PH domain relative to the catalytic domain. These distinct conformations of full-length PDK1 can influence the interaction and phosphorylation of substrates. Finally, we critically discuss recent findings proposing that PIP3 can directly regulate the activity of PDK1, which contradicts extensive in vitro and in vivo studies conducted over the years.
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Affiliation(s)
- Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
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2
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Martínez-Arenas L, Bayascas JR. Capturing conformational transitions of full-length PDK1 that dictate kinase substrate selectivity. Sci Signal 2023; 16:eadh5114. [PMID: 37311035 DOI: 10.1126/scisignal.adh5114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
PDK1 is a constitutively active master kinase that can phosphorylate and activate as many as 24 enzymes, all belonging to the AGC family of serine-threonine protein kinases. In this issue of Science Signaling, Sacerdoti et al. uncover how allosteric communication between different functional domains directs the selectivity of PDK1 toward particular subsets of substrates.
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Affiliation(s)
- Laura Martínez-Arenas
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Jose R Bayascas
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
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3
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Gordon MT, Ziemba BP, Falke JJ. PDK1:PKCα heterodimer association-dissociation dynamics in single-molecule diffusion tracks on a target membrane. Biophys J 2023:S0006-3495(23)00090-5. [PMID: 36733254 DOI: 10.1016/j.bpj.2023.01.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 12/01/2022] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Previous studies have documented the formation of a heterodimer between the two protein kinases PDK1 and PKCα on a lipid bilayer containing their target lipids. This work investigates the association-dissociation kinetics of this PDK1:PKCα heterodimer. The approach monitors the two-dimensional diffusion of single, membrane-associated PDK1 molecules for diffusivity changes as PKCα molecules bind and unbind. In the absence of PKCα, a membrane-associated PDK1 molecule exhibits high diffusivity (or large diffusion constant, D) because its membrane-contacting PH domain binds the target PIP3 lipid headgroup with little bilayer penetration, yielding minimal frictional drag against the bilayer. In contrast, membrane-associated PKCα contacts the bilayer via its C1A, C1B, and C2 domains, which each bind at least one target lipid with significant bilayer insertion, yielding a large frictional drag and low diffusivity. The present findings reveal that individual fluor-PDK1 molecules freely diffusing on the membrane surface undergo reversible switching between distinct high and low diffusivity states, corresponding to the PDK1 monomer and the PDK1:PKCα heterodimer, respectively. The observed single-molecule diffusion trajectories are converted to step length time courses, then subjected to two-state, hidden Markov modeling and dwell time analysis. The findings reveal that both the PDK1 monomer state and the PDK1:PKCα heterodimer state decay via simple exponential kinetics, yielding estimates of rate constants for state switching in both directions. Notably, the PDK1:PKCα heterodimer has been shown to competitively inhibit PDK1 phosphoactivation of AKT1, and is believed to play a tumor suppressor role by limiting excess activation of the highly oncogenic PDK1/AKT1/mTOR pathway. Thus, the present elucidation of the PDK1:PKCα association-dissociation kinetics has important biological and medical implications. More broadly, the findings illustrate the power of single-molecule diffusion measurements to reveal the kinetics of association-dissociation events in membrane signaling reactions that yield a large change in diffusive mobility.
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Affiliation(s)
- Moshe T Gordon
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado
| | - Brian P Ziemba
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado
| | - Joseph J Falke
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado.
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4
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Beyond controlling cell size: functional analyses of S6K in tumorigenesis. Cell Death Dis 2022; 13:646. [PMID: 35879299 PMCID: PMC9314331 DOI: 10.1038/s41419-022-05081-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 01/21/2023]
Abstract
As a substrate and major effector of the mammalian target of rapamycin complex 1 (mTORC1), the biological functions of ribosomal protein S6 kinase (S6K) have been canonically assigned for cell size control by facilitating mRNA transcription, splicing, and protein synthesis. However, accumulating evidence implies that diverse stimuli and upstream regulators modulate S6K kinase activity, leading to the activation of a plethora of downstream substrates for distinct pathobiological functions. Beyond controlling cell size, S6K simultaneously plays crucial roles in directing cell apoptosis, metabolism, and feedback regulation of its upstream signals. Thus, we comprehensively summarize the emerging upstream regulators, downstream substrates, mouse models, clinical relevance, and candidate inhibitors for S6K and shed light on S6K as a potential therapeutic target for cancers.
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Wang H, Chi L, Yu F, Dai H, Si X, Gao C, Wang Z, Liu L, Zheng J, Ke Y, Liu H, Zhang Q. The overview of Mitogen-activated extracellular signal-regulated kinase (MEK)-based dual inhibitor in the treatment of cancers. Bioorg Med Chem 2022; 70:116922. [PMID: 35849914 DOI: 10.1016/j.bmc.2022.116922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/01/2022] [Accepted: 07/06/2022] [Indexed: 11/02/2022]
Abstract
Mitogen-activated extracellular signal-regulated kinase 1 and 2 (MEK1/2) are the critical components of the mitogen-activated protein kinase/extracellular signal-regulated kinase 1 and 2 (MAPK/ERK1/2) signaling pathway which is one of the well-characterized kinase cascades regulating cell proliferation, differentiation, growth, metabolism, survival and mobility both in normal and cancer cells. The aberrant activation of MAPK/ERK1/2 pathway is a hallmark of numerous human cancers, therefore targeting the components of this pathway to inhibit its dysregulation is a promising strategy for cancer treatment. Enormous efforts have been done in the development of MEK1/2 inhibitors and encouraging advancements have been made, including four inhibitors approved for clinical use. However, due to the multifactorial property of cancer and rapidly arising drug resistance, the clinical efficacy of these MEK1/2 inhibitors as monotherapy are far from ideal. Several alternative strategies have been developed to improve the limited clinical efficacy, including the dual inhibitor which is a single drug molecule able to simultaneously inhibit two targets. In this review, we first introduced the activation and function of the MAPK/ERK1/2 components and discussed the advantages of MEK1/2-based dual inhibitors compared with the single inhibitors and combination therapy in the treatment of cancers. Then, we overviewed the MEK1/2-based dual inhibitors for the treatment of cancers and highlighted the theoretical basis of concurrent inhibition of MEK1/2 and other targets for development of these dual inhibitors. Besides, the status and results of these dual inhibitors in both preclinical and clinical studies were also the focus of this review.
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Affiliation(s)
- Hao Wang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Lingling Chi
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Fuqiang Yu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Hongling Dai
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Xiaojie Si
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Chao Gao
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Zhengjie Wang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Limin Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Jiaxin Zheng
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China
| | - Yu Ke
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China.
| | - Hongmin Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China; State Key Laboratory of Esophageal Cancer Prevention & Treatment, Zhengzhou 450052, China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Zhengzhou 450001, China.
| | - Qiurong Zhang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China; Collaborative Innovation Center of New Drug Research and Safety Evaluation of Henan Province, Zhengzhou 450001, China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Zhengzhou 450001, China.
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Mamidi MK, Mahmud H, Maiti GP, Mendez MT, Fernandes SM, Vesely SK, Holter-Chakrabarty J, Brown JR, Ghosh AK. Idelalisib activates AKT via increased recruitment of PI3Kδ/PI3Kβ to BCR signalosome while reducing PDK1 in post-therapy CLL cells. Leukemia 2022; 36:1806-1817. [PMID: 35568768 PMCID: PMC10874218 DOI: 10.1038/s41375-022-01595-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/08/2022]
Abstract
Idelalisib targets PI3Kδ in the BCR pathway generating only a partial response in CLL patients, indicating that the leukemic cells may have evolved escape signals. Indeed, we detected increased activation of AKT accompanied by upregulation of MYC/BCL2 in post-therapy CLL cells from patients treated with idelalisib/ofatumumab. To unravel the mechanism of increased AKT-activation, we studied the impact of idelalisib on a CLL-derived cell line, MEC1, as a model. After an initial inhibition, AKT-activation level was restored in idelalisib-treated MEC1 cells in a time-dependent manner. As BCAP (B-cell adaptor for PI3K) and CD19 recruit PI3Kδ to activate AKT upon BCR-stimulation, we examined if idelalisib-treatment altered PI3Kδ-recruitment. Immunoprecipitation of BCAP/CD19 from idelalisib-treated MEC1 cells showed increased recruitment of PI3Kδ in association with PI3Kβ, but not PI3Kα or PI3Kγ and that, targeting both PI3Kδ with PI3Kβ inhibited AKT-reactivation. We detected similar, patient-specific recruitment pattern of PI3K-isoforms by BCAP/CD19 in post-idelalisib CLL cells with increased AKT-activation. Interestingly, a stronger inhibitory effect of idelalisib on P-AKT (T308) than S473 was discernible in idelalisib-treated cells despite increased recruitment of PI3Kδ/PI3Kβ and accumulation of phosphatidylinositol-3,4,5-triphosphate; which could be attributed to reduced PDK1 activity. Thus, administration of isoform-specific inhibitors may prove more effective strategy for treating CLL patients.
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Affiliation(s)
- Murali K Mamidi
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Hasan Mahmud
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Guru P Maiti
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mariana T Mendez
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Stacey M Fernandes
- Division of Hematologic Malignancies and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Sara K Vesely
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | | | - Jennifer R Brown
- Division of Hematologic Malignancies and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Asish K Ghosh
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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7
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Reducing PDK1/Akt Activity: An Effective Therapeutic Target in the Treatment of Alzheimer's Disease. Cells 2022; 11:cells11111735. [PMID: 35681431 PMCID: PMC9179555 DOI: 10.3390/cells11111735] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/16/2022] [Accepted: 05/24/2022] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a common age-related neurodegenerative disease that leads to memory loss and cognitive function damage due to intracerebral neurofibrillary tangles (NFTs) and amyloid-β (Aβ) protein deposition. The phosphoinositide-dependent protein kinase (PDK1)/protein kinase B (Akt) signaling pathway plays a significant role in neuronal differentiation, synaptic plasticity, neuronal survival, and neurotransmission via the axon–dendrite axis. The phosphorylation of PDK1 and Akt rises in the brain, resulting in phosphorylation of the TNF-α-converting enzyme (TACE) at its cytoplasmic tail (the C-terminal end), changing its internalization as well as its trafficking. The current review aimed to explain the mechanisms of the PDK1/Akt/TACE signaling axis that exerts its modulatory effect on AD physiopathology. We provide an overview of the neuropathological features, genetics, Aβ aggregation, Tau protein hyperphosphorylation, neuroinflammation, and aging in the AD brain. Additionally, we summarized the phosphoinositide 3-kinase (PI3K)/PDK1/Akt pathway-related features and its molecular mechanism that is dependent on TACE in the pathogenesis of AD. This study reviewed the relationship between the PDK1/Akt signaling pathway and AD, and discussed the role of PDK1/Akt in resisting neuronal toxicity by suppressing TACE expression in the cell membrane. This work also provides a perspective for developing new therapeutics targeting PDK1/Akt and TACE for the treatment of AD.
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8
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Activation of the essential kinase PDK1 by phosphoinositide-driven trans-autophosphorylation. Nat Commun 2022; 13:1874. [PMID: 35387990 PMCID: PMC8986801 DOI: 10.1038/s41467-022-29368-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/08/2022] [Indexed: 12/18/2022] Open
Abstract
3-phosphoinositide-dependent kinase 1 (PDK1) is an essential serine/threonine protein kinase, which plays a crucial role in cell growth and proliferation. It is often referred to as a ‘master’ kinase due to its ability to activate at least 23 downstream protein kinases implicated in various signaling pathways. In this study, we have elucidated the mechanism of phosphoinositide-driven PDK1 auto-activation. We show that PDK1 trans-autophosphorylation is mediated by a PIP3-mediated face-to-face dimer. We report regulatory motifs in the kinase-PH interdomain linker that allosterically activate PDK1 autophosphorylation via a linker-swapped dimer mechanism. Finally, we show that PDK1 is autoinhibited by its PH domain and that positive cooperativity of PIP3 binding drives switch-like activation of PDK1. These results imply that the PDK1-mediated activation of effector kinases, including Akt, PKC, Sgk, S6K and RSK, many of whom are not directly regulated by phosphoinositides, is also likely to be dependent on PIP3 or PI(3,4)P2. The essential protein kinase PDK1 is activated by phospoinositide-mediated dimerization and trans-autophosphorylation. Here, the authors show that in the absence of PIP3 or PI(3,4)P2 phosphoinositides, PDK1 is maintained in an inactive, autoinhibited conformation in the cytosol.
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Guo J, Cheng J, Zheng N, Zhang X, Dai X, Zhang L, Hu C, Wu X, Jiang Q, Wu D, Okada H, Pandolfi PP, Wei W. Copper Promotes Tumorigenesis by Activating the PDK1-AKT Oncogenic Pathway in a Copper Transporter 1 Dependent Manner. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2004303. [PMID: 34278744 PMCID: PMC8456201 DOI: 10.1002/advs.202004303] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 05/25/2021] [Indexed: 05/13/2023]
Abstract
Copper plays pivotal roles in metabolic homoeostasis, but its potential role in human tumorigenesis is not well defined. Here, it is revealed that copper activates the phosphoinositide 3-kinase (PI3K)-protein kinase B (PKB, also termed AKT) oncogenic signaling pathway to facilitate tumorigenesis. Mechanistically, copper binds 3-phosphoinositide dependent protein kinase 1 (PDK1), in turn promotes PDK1 binding and subsequently activates its downstream substrate AKT to facilitate tumorigenesis. Blocking the copper transporter 1 (CTR1)-copper axis by either depleting CTR1 or through the use of copper chelators diminishes the AKT signaling and reduces tumorigenesis. In support of an oncogenic role for CTR1, the authors find that CTR1 is abnormally elevated in breast cancer, and is subjected by NEDD4 like E3 ubiquitin protein ligase (Nedd4l)-mediated negative regulation through ubiquitination and subsequent degradation. Accordingly, Nedd4l displays a tumor suppressive function by suppressing the CTR1-AKT signaling. Thus, the findings identify a novel regulatory crosstalk between the Nedd4l-CTR1-copper axis and the PDK1-AKT oncogenic signaling, and highlight the therapeutic relevance of targeting the CTR1-copper node for the treatment of hyperactive AKT-driven cancers.
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Affiliation(s)
- Jianping Guo
- Department of PathologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
- Institute of Precision Medicinethe First Affiliated HospitalSun Yat‐sen UniversityGuangzhouGuangdong510275China
| | - Ji Cheng
- Department of PathologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
- Department of Gastrointestinal SurgeryUnion HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei430022China
| | - Nana Zheng
- National Clinical Research Center for Hematologic DiseasesJiangsu Institute of HematologyThe First Affiliated Hospital of Soochow UniversitySuzhouJiangsu215000China
| | - Xiaomei Zhang
- Institute of Precision Medicinethe First Affiliated HospitalSun Yat‐sen UniversityGuangzhouGuangdong510275China
| | - Xiaoming Dai
- Department of PathologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
| | - Linli Zhang
- Department of OncologyTongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei430030China
| | - Changjiang Hu
- Department of PathologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
| | - Xueji Wu
- Institute of Precision Medicinethe First Affiliated HospitalSun Yat‐sen UniversityGuangzhouGuangdong510275China
| | - Qiwei Jiang
- Institute of Precision Medicinethe First Affiliated HospitalSun Yat‐sen UniversityGuangzhouGuangdong510275China
| | - Depei Wu
- National Clinical Research Center for Hematologic DiseasesJiangsu Institute of HematologyThe First Affiliated Hospital of Soochow UniversitySuzhouJiangsu215000China
| | - Hitoshi Okada
- Department of BiochemistryKindai University Faculty of Medicine377‐2 Ohno‐HigashiOsaka‐SayamaOsaka589‐8511Japan
| | - Pier Paolo Pandolfi
- Division of GeneticsDepartment of MedicineBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
| | - Wenyi Wei
- Department of PathologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA02215USA
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Baffi TR, Newton AC. mTOR Regulation of AGC Kinases: New Twist to an Old Tail. Mol Pharmacol 2021; 101:213-218. [PMID: 34155089 DOI: 10.1124/molpharm.121.000310] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/09/2021] [Indexed: 11/22/2022] Open
Abstract
The family of AGC kinases not only regulate cellular biology by phosphorylating substrates, but are themselves controlled by phosphorylation. Phosphorylation generally occurs at two conserved regions in these kinases: a loop near the entrance to the active site, termed the activation loop, that correctly aligns residues for catalysis, and a C-terminal tail whose phosphorylation at a site termed the hydrophobic motif stabilizes the active conformation. Whereas phosphorylation of the activation loop is well established to be catalyzed by the phosphoinositide-dependent kinase 1 (PDK1), the mechanism of phosphorylation of the C-tail hydrophobic motif has been controversial. For a subset of AGC kinases, which includes most protein kinase C (PKC) isozymes and Akt, phosphorylation of the hydrophobic motif in cells was shown to depend on mTORC2 over 15 years ago, yet whether by direct phosphorylation or by another mechanism has remained elusive. The recent identification of a novel and evolutionarily conserved phosphorylation site on the C-tail termed the TOR-Interaction Motif (TIM) has finally unraveled the mystery of how mTORC2 regulates its client kinases. mTORC2 does not directly phosphorylate the hydrophobic motif, rather it converts kinases such as PKC and Akt into a conformation that can ultimately autophosphorylate at the hydrophobic motif. Identification of the direct mTOR phosphorylation that facilitates auto-regulation of the C-tail hydrophobic motif revises the activation mechanisms of mTOR-regulated AGC kinases. This new twist to an old tail opens avenues for therapeutic intervention. Significance Statement The enzyme mTORC2 has been an enigmatic regulator of AGC kinases such as protein kinase C (PKC) and Akt. The recent discovery of a motif named the TOR Interaction Motif in the C-tail of these kinases solves the mystery: mTORC2 marks these kinases for maturity by, ultimately, facilitating autophosphorylation another C-tail site, the hydrophobic motif.
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11
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Hart JE, Gardner KH. Lighting the way: Recent insights into the structure and regulation of phototropin blue light receptors. J Biol Chem 2021; 296:100594. [PMID: 33781746 PMCID: PMC8086140 DOI: 10.1016/j.jbc.2021.100594] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023] Open
Abstract
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired. Phototropins combine two blue-light-sensing Light-Oxygen-Voltage (LOV) domains (LOV1 and LOV2) and a C-terminal serine/threonine kinase domain, using the LOV domains to control the catalytic activity of the kinase. While much is known about the structure and photochemistry of the light-perceiving LOV domains, particularly in how activation of the LOV2 domain triggers the unfolding of alpha helices that communicate the light signal to the kinase domain, many questions about phot structure and mechanism remain. Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe. We discuss this and other advances that have improved structural and mechanistic understanding of phot regulation in this review, along with the challenges that will have to be overcome to obtain high-resolution structural information on these exciting photoreceptors. Such information will be essential to advancing fundamental understanding of plant physiology while enabling engineering efforts at both the whole plant and molecular levels.
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Affiliation(s)
- Jaynee E Hart
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Kevin H Gardner
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; Department of Chemistry and Biochemistry, City College of New York, New York, USA; PhD Programs in Biochemistry, Chemistry, and Biology, Graduate Center, City University of New York, New York, USA.
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12
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P2 × 7 Receptor Inhibits Astroglial Autophagy via Regulating FAK- and PHLPP1/2-Mediated AKT-S473 Phosphorylation Following Kainic Acid-Induced Seizures. Int J Mol Sci 2020; 21:ijms21186476. [PMID: 32899862 PMCID: PMC7555659 DOI: 10.3390/ijms21186476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 12/31/2022] Open
Abstract
Recently, we have reported that blockade/deletion of P2X7 receptor (P2X7R), an ATP-gated ion channel, exacerbates heat shock protein 25 (HSP25)-mediated astroglial autophagy (clasmatodendrosis) following kainic acid (KA) injection. In P2X7R knockout (KO) mice, prolonged astroglial HSP25 induction exerts 5′ adenosine monophosphate-activated protein kinase/unc-51 like autophagy activating kinase 1-mediated autophagic pathway independent of mammalian target of rapamycin (mTOR) activity following KA injection. Sustained HSP25 expression also enhances AKT-serine (S) 473 phosphorylation leading to astroglial autophagy via glycogen synthase kinase-3β/bax interacting factor 1 signaling pathway. However, it is unanswered how P2X7R deletion induces AKT-S473 hyperphosphorylation during autophagic process in astrocytes. In the present study, we found that AKT-S473 phosphorylation was increased by enhancing activity of focal adhesion kinase (FAK), independent of mTOR complex (mTORC) 1 and 2 activities in isolated astrocytes of P2X7R knockout (KO) mice following KA injection. In addition, HSP25 overexpression in P2X7R KO mice acted as a chaperone of AKT, which retained AKT-S473 phosphorylation by inhibiting the pleckstrin homology domain and leucine-rich repeat protein phosphatase (PHLPP) 1- and 2-binding to AKT. Therefore, our findings suggest that P2X7R may be a fine-tuner of AKT-S473 activity during astroglial autophagy by regulating FAK phosphorylation and HSP25-mediated inhibition of PHLPP1/2-AKT binding following KA treatment.
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13
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Kim K, Park SG, Park BC, Kim JH, Kim S. Serine 389 phosphorylation of 3-phosphoinositide-dependent kinase 1 by UNC-51-like kinase 1 affects its ability to regulate Akt and p70 S6kinase. BMB Rep 2020. [PMID: 32317083 PMCID: PMC7396916 DOI: 10.5483/bmbrep.2020.53.7.299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Phosphorylation of the signaling component by protein kinase often leads to a kinase cascade or feedback loop. 3-Phosphoinositide-dependent kinase 1 (PDK1) signaling pathway diverges into various kinases including Akt and p70 S6 kinase (p70S6k). However, the PDK1 feedback mechanism remains elusive. Here, we demonstrated that UNC-51-like kinase (ULK1), an autophagy initiator kinase downstream of mechanistic target of rapamycin (mTOR), directly phosphorylated PDK1 on serine 389 at the linker region. Furthermore, our data showed that this phosphorylation affected the kinase activity of PDK1 toward downstream substrates. These results suggest a possible negative feedback loop between PDK1 and ULK1.
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Affiliation(s)
- Kidae Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Proteome Structural biology, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Sung Goo Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Byoung Chul Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Proteome Structural biology, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Jeong-Hoon Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Sunhong Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
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Furlong RM, Lindsay A, Anderson KE, Hawkins PT, Sullivan AM, O'Neill C. The Parkinson's disease gene PINK1 activates Akt via PINK1 kinase-dependent regulation of the phospholipid PI(3,4,5)P 3. J Cell Sci 2019; 132:jcs.233221. [PMID: 31540955 DOI: 10.1242/jcs.233221] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/12/2019] [Indexed: 12/12/2022] Open
Abstract
Akt signalling is central to cell survival, metabolism, protein and lipid homeostasis, and is impaired in Parkinson's disease (PD). Akt activation is reduced in the brain in PD, and by many PD-causing genes, including PINK1 This study investigated the mechanisms by which PINK1 regulates Akt signalling. Our results reveal for the first time that PINK1 constitutively activates Akt in a PINK1-kinase dependent manner in the absence of growth factors, and enhances Akt activation in normal growth medium. In PINK1-modified MEFs, agonist-induced Akt signalling failed in the absence of PINK1, due to PINK1 kinase-dependent increases in PI(3,4,5)P3 at both plasma membrane and Golgi being significantly impaired. In the absence of PINK1, PI(3,4,5)P3 levels did not increase in the Golgi, and there was significant Golgi fragmentation, a recognised characteristic of PD neuropathology. PINK1 kinase activity protected the Golgi from fragmentation in an Akt-dependent fashion. This study demonstrates a new role for PINK1 as a primary upstream activator of Akt via PINK1 kinase-dependent regulation of its primary activator PI(3,4,5)P3, providing novel mechanistic information on how loss of PINK1 impairs Akt signalling in PD.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Rachel M Furlong
- School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork City T12 YT20, Ireland.,Department of Anatomy and Neuroscience, Western Gateway Building, University College Cork, Cork City T12 XF62, Ireland.,Cork NeuroScience Centre, University College Cork, Cork City T12 YT20, Ireland
| | - Andrew Lindsay
- School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork City T12 YT20, Ireland
| | - Karen E Anderson
- Signalling Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | | | - Aideen M Sullivan
- Department of Anatomy and Neuroscience, Western Gateway Building, University College Cork, Cork City T12 XF62, Ireland.,Cork NeuroScience Centre, University College Cork, Cork City T12 YT20, Ireland
| | - Cora O'Neill
- School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork City T12 YT20, Ireland .,Cork NeuroScience Centre, University College Cork, Cork City T12 YT20, Ireland
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15
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Picco ME, Castro MV, Quezada MJ, Barbero G, Villanueva MB, Fernández NB, Kim H, Lopez-Bergami P. STAT3 enhances the constitutive activity of AGC kinases in melanoma by transactivating PDK1. Cell Biosci 2019; 9:3. [PMID: 30622697 PMCID: PMC6317239 DOI: 10.1186/s13578-018-0265-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/21/2018] [Indexed: 01/26/2023] Open
Abstract
Background The PI3K/Akt and the STAT3 pathways are functionally associated in many tumor types. Both in vitro and in vivo studies have revealed that either biochemical or genetic manipulation of the STAT3 pathway activity induce changes in the same direction in Akt activity. However, the implicated mechanism has been poorly characterized. Our goal was to characterize the precise mechanism linking STAT3 with the activity of Akt and other AGC kinases in cancer using melanoma cells as a model. Results We show that active STAT3 is constitutively bound to the PDK1 promoter and positively regulate PDK1 transcription through two STAT3 responsive elements. Transduction of WM9 and UACC903 melanoma cells with STAT3-small hairpin RNA decreased both PDK1 mRNA and protein levels. STAT3 knockdown also induced a decrease of the phosphorylation of AGC kinases Akt, PKC, and SGK. The inhibitory effect of STAT3 silencing on Akt phosphorylation was restored by HA-PDK1. Along this line, HA-PDK1 expression significantly blocked the cell death induced by dacarbazine plus STAT3 knockdown. This effect might be mediated by Bcl2 proteins since HA-PDK1 rescued Bcl2, Bcl-XL, and Mcl1 levels that were down-regulated upon STAT3 silencing. Conclusions We show that PDK1 is a transcriptional target of STAT3, linking STAT3 pathway with AGC kinases activity in melanoma. These data provide further rationale for the ongoing effort to therapeutically target STAT3 and PDK1 in melanoma and, possibly, other malignancies. Electronic supplementary material The online version of this article (10.1186/s13578-018-0265-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- María Elisa Picco
- 1Instituto de Medicina y Biología Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - María Victoria Castro
- 2Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, CONICET, Hidalgo 775, 6th Floor, Lab 602, Buenos Aires, Argentina
| | - María Josefina Quezada
- 2Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, CONICET, Hidalgo 775, 6th Floor, Lab 602, Buenos Aires, Argentina
| | - Gastón Barbero
- 2Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, CONICET, Hidalgo 775, 6th Floor, Lab 602, Buenos Aires, Argentina
| | - María Belén Villanueva
- 2Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, CONICET, Hidalgo 775, 6th Floor, Lab 602, Buenos Aires, Argentina
| | - Natalia Brenda Fernández
- 1Instituto de Medicina y Biología Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Hyungsoo Kim
- 3Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA USA
| | - Pablo Lopez-Bergami
- 2Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, CONICET, Hidalgo 775, 6th Floor, Lab 602, Buenos Aires, Argentina
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16
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Gocher AM, Azabdaftari G, Euscher LM, Dai S, Karacosta LG, Franke TF, Edelman AM. Akt activation by Ca 2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) in ovarian cancer cells. J Biol Chem 2017. [PMID: 28634229 DOI: 10.1074/jbc.m117.778464] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Hyperactivation of Akt is associated with oncogenic changes in the growth, survival, and chemoresistance of cancer cells. The PI3K/phosphoinositide-dependent kinase (PDK) 1 pathway represents the canonical mechanism for phosphorylation of Akt at its primary activation site, Thr-308. We observed that Ca2+/calmodulin (CaM)-dependent protein kinase kinase 2 (β) (CaMKK2) is highly expressed in high-grade serous ovarian cancer, and we investigated its role in Akt activation in ovarian cancer (OVCa) cell lines (OVCAR-3, SKOV-3, and Caov-3). Knockdown or pharmacological inhibition of CaMKK2 produced phenotypes expected of Akt inhibition, including reductions in cell growth and cell viability and in the regulation of Akt downstream targets involved in G1/S transition and apoptosis. CaMKK2 knockdown or inhibition decreased Akt phosphorylation at Thr-308 and Ser-473 to extents similar to those of PDK1 knockdown or PI3K inhibition. Combined CaMKK2 and PDK1 knockdown or CaMKK and PI3K inhibition, respectively, produced additive effects on p-Akt and cell growth, consistent with direct Akt phosphorylation by CaMKK2. This conclusion was supported by the absence of effects of CaMKK2 knockdown/inhibition on alternative means of activating Akt via p-Akt Thr-450, p-PDK1 Ser-241, or p-IRS1 Ser-636/639. Recombinant CaMKK2 directly activated recombinant Akt by phosphorylation at Thr-308 in a Ca2+/CaM-dependent manner. In OVCa cells, p-Akt Thr-308 was significantly inhibited by intracellular Ca2+i chelation or CaM inhibition. Ionomycin-induced Ca2+ influx promoted p-Akt, an effect blocked by PDK1, and/or CaMKK2, siRNAs, and by PI3K and/or CaMKK inhibitors. CaMKK2 knockdown potentiated the effects of the chemotherapeutic drugs carboplatin and PX-866 to reduce proliferation and survival of OVCa cells.
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Affiliation(s)
- Angela M Gocher
- From the Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214
| | - Gissou Azabdaftari
- Department of Pathology and Laboratory Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Lindsey M Euscher
- From the Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214
| | - Shuhang Dai
- From the Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214
| | - Loukia G Karacosta
- From the Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214
| | - Thomas F Franke
- Department of Psychiatry, Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016
| | - Arthur M Edelman
- From the Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214,.
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17
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Di Blasio L, Gagliardi PA, Puliafito A, Primo L. Serine/Threonine Kinase 3-Phosphoinositide-Dependent Protein Kinase-1 (PDK1) as a Key Regulator of Cell Migration and Cancer Dissemination. Cancers (Basel) 2017; 9:cancers9030025. [PMID: 28287465 PMCID: PMC5366820 DOI: 10.3390/cancers9030025] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 02/03/2023] Open
Abstract
Dissecting the cellular signaling that governs the motility of eukaryotic cells is one of the fundamental tasks of modern cell biology, not only because of the large number of physiological processes in which cell migration is crucial, but even more so because of the pathological ones, in particular tumor invasion and metastasis. Cell migration requires the coordination of at least four major processes: polarization of intracellular signaling, regulation of the actin cytoskeleton and membrane extension, focal adhesion and integrin signaling and contractile forces generation and rear retraction. Among the molecular components involved in the regulation of locomotion, the phosphatidylinositol-3-kinase (PI3K) pathway has been shown to exert fundamental role. A pivotal node of such pathway is represented by the serine/threonine kinase 3-phosphoinositide-dependent protein kinase-1 (PDPK1 or PDK1). PDK1, and the majority of its substrates, belong to the AGC family of kinases (related to cAMP-dependent protein kinase 1, cyclic Guanosine monophosphate-dependent protein kinase and protein kinase C), and control a plethora of cellular processes, downstream either to PI3K or to other pathways, such as RAS GTPase-MAPK (mitogen-activated protein kinase). Interestingly, PDK1 has been demonstrated to be crucial for the regulation of each step of cell migration, by activating several proteins such as protein kinase B/Akt (PKB/Akt), myotonic dystrophy-related CDC42-binding kinases alpha (MRCKα), Rho associated coiled-coil containing protein kinase 1 (ROCK1), phospholipase C gamma 1 (PLCγ1) and β3 integrin. Moreover, PDK1 regulates cancer cell invasion as well, thus representing a possible target to prevent cancer metastasis in human patients. The aim of this review is to summarize the various mechanisms by which PDK1 controls the cell migration process, from cell polarization to actin cytoskeleton and focal adhesion regulation, and finally, to discuss the evidence supporting a role for PDK1 in cancer cell invasion and dissemination.
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Affiliation(s)
- Laura Di Blasio
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
| | | | | | - Luca Primo
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
- Department of Oncology, University of Torino, 10043 Orbassano, Torino, Italy.
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18
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Molecular characterization of the Haemonchus contortus phosphoinositide-dependent protein kinase-1 gene (Hc-pdk-1). Parasit Vectors 2016; 9:65. [PMID: 26842781 PMCID: PMC4741024 DOI: 10.1186/s13071-016-1351-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/28/2016] [Indexed: 12/22/2022] Open
Abstract
Background Phosphoinositide-dependent protein kinase-1 (PDK-1), which functions downstream of phosphoinositide 3-kinase (AGE-1) and activates protein kinases of the AGC family, plays critical roles in regulating biology processes, such as metabolism, growth, development and survival. In the free-living nematode Caenorhabditis elegans, PDK-1 is a key component of the insulin-like signalling pathway, regulating the entry into and exit from dauer (arrested development). Although it is proposed that similar molecular mechanisms control the transition from the free-living to the parasitic stages of nematodes, nothing is known about PDK-1 in Haemonchus contortus, a socioeconomically important gastric nematode of ruminants. Methods Here, we isolated and characterized the pdk-1 gene (Hc-pdk-1) and its inferred product (Hc-PDK-1) from H. contortus. Using in vitro and in vivo methods, we then studied the transcriptional profiles of Hc-pdk-1 and anatomical gene expression patterns of Hc-PDK-1 in different developmental stages of C. elegans. Results In silico analysis of Hc-PDK-1 displayed conserved functional domains, such as protein kinase and pleckstrin homology (PH) domains and two predicted phosphorylation sites (Thr226/Tyr229), which are crucial for the phosphorylation of downstream signalling. The Hc-pdk-1 gene is transcribed in all of the main developmental stages of H. contortus, with its highest transcription in the infective third-stage larvae (iL3) compared with other stages. Transgene constructs, in which respective promoters were fused to the coding sequence for green fluorescent protein (GFP), were used to transform C. elegans, and to localize and compare the expression of Hc-pdk-1 and Ce-pdk-1. The expression of GFP under the control of the Hc-pdk-1 promoter was localized to the intestine, and head and tail neurons, contrasting somewhat the profile for the C. elegans ortholog, which is expressed in pharynx, intestine and head and tail neurons. Conclusions This is the first characterization of pdk-1/PDK-1 from a trichostrongyloid nematode. Taken together, the findings from this study provide a first glimpse of the involvement of Hc-pdk-1 in the insulin-like signalling pathway in H. contortus. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1351-6) contains supplementary material, which is available to authorized users.
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Xu Z, Liao B, Zhang R, Yao J, Shi R, Wang L. Expression of 3-phosphoinositide-dependent protein kinase 1 in colorectal cancer as a potential therapeutic target. Med Oncol 2015; 32:198. [PMID: 26055151 DOI: 10.1007/s12032-015-0645-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 05/21/2015] [Indexed: 01/05/2023]
Abstract
3-Phosphoinositide-dependent protein kinase 1 (PDK1) is centrally involved in cancer progression, including proliferation, apoptosis and invasion. However, its expression pattern and possible cellular functions in human colorectal cancer remain unclear. In the present study, we show that PDK1 expression is up-regulated at both mRNA and protein levels in colorectal cancer clinical specimens and cell lines. Transient knockdown of PDK1 suppresses cellular growth, induces cellular apoptosis and causes abnormal cell cycle distribution. Meanwhile, decreased PDK1 level is closely associated with reduced Akt/cyclin D1 activity. Activating AKT activity and reintroducing cyclin D1 expression significantly compromised the oncogenic activity induced by PDK1. Together, our findings elucidate a key role for PDK1 in colorectal cellular functions trigged by the Akt/cyclin D1 pathway, thus providing a novel insight of PDK1 in colorectal carcinogenesis.
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Affiliation(s)
- Zhenglei Xu
- Department of Gastroenterology, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, 1017#, North Dongmen Road, Shenzhen, 518000, Guangdong Province, People's Republic of China
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20
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Hossen MJ, Kim SC, Yang S, Kim HG, Jeong D, Yi YS, Sung NY, Lee JO, Kim JH, Cho JY. PDK1 disruptors and modulators: a patent review. Expert Opin Ther Pat 2015; 25:513-37. [PMID: 25684022 DOI: 10.1517/13543776.2015.1014801] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION 3-Phosphoinositide-dependent kinase 1 (PDK1) is a master regulator of the AGC protein kinase family and is a critical activator of multiple pro-survival and oncogenic protein kinases, for which it has garnered considerable interest as an oncology drug target. AREAS COVERED This manuscript reviews small molecule patent literature disclosures between October 2011 and September 2014 for both PDK1 activators and inhibitors and restates the selective patents published before September 2011. PDK1 modulators are organized according to pharmaceutical company and chemical structural class. EXPERT OPINION Many academic institutions and pharmaceutical companies continue to research into the development of small molecules that can function as PDK1 inhibitors or modulators. To date, >50 patent publications on PDK1 disruptors and modulators have been published since the protein was first discovered in 1998. Most of these molecules act as ATP mimetics, forming similar hydrogen bonding patterns to PDK1 as ATP and functioning as hydrophobic pharmacophores. To achieve selectivity in PDK1 inhibition, the discovery of binding pockets structurally distinctive from the ATP site is a challenging but promising strategy.
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Affiliation(s)
- Muhammad Jahangir Hossen
- Sungkyunkwan University, Department of Genetic Engineering , 300 Chuncheon-Dong, Suwon 440-746 , Korea +82 31 290 7868 ; +82 31 290 7870 ;
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21
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Calleja V, Laguerre M, de Las Heras-Martinez G, Parker PJ, Requejo-Isidro J, Larijani B. Acute regulation of PDK1 by a complex interplay of molecular switches. Biochem Soc Trans 2014; 42:1435-40. [PMID: 25233428 DOI: 10.1042/bst20140222] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphoinositide-dependent kinase 1 (PDK1) is the master regulator of at least 23 other AGC kinases whose downstream signalling has often been implicated in various diseases and in particular in cancer. Therefore there has been great interest in determining how PDK1 is controlled and how it regulates its substrates spatially and temporally. The understanding of these mechanisms could offer new possibilities for therapeutic intervention. Over the years, a more comprehensive view of the mechanisms involved in the regulation of PDK1 has emerged and these comprise serine/threonine as well as tyrosine phosphorylation, subcellular localization, regulator binding and conformation status. In the present review, we discuss how various molecular mechanisms are together responsible for the conformational regulation behind the activation of PDK1 in cells.
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Affiliation(s)
| | - Michel Laguerre
- ‡Institut Européen de Chimie et Biologie, Université de Bordeaux, UMR 5248, 2 rue Robert Escarpit, F-33607 Pessac, France
| | | | | | - Jose Requejo-Isidro
- §Biophotonics Lab, Unidad de Biofísica CSIC-UPV/EHU, Barrio de Sarriena s/n, 48940 Leioa, Spain
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Lin G, Brownsey RW, MacLeod KM. Complex regulation of PKCβ2 and PDK-1/AKT by ROCK2 in diabetic heart. PLoS One 2014; 9:e86520. [PMID: 24466133 PMCID: PMC3896488 DOI: 10.1371/journal.pone.0086520] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 12/15/2013] [Indexed: 01/13/2023] Open
Abstract
Objectives The RhoA/ROCK pathway contributes to diabetic cardiomyopathy in part by promoting the sustained activation of PKCβ2 but the details of their interaction are unclear. The purpose of this study was to investigate if over-activation of ROCK in the diabetic heart leads to direct phosphorylation and activation of PKCβ2, and to determine if their interaction affects PDK-1/Akt signaling. Methods Regulation by ROCK of PKCβ2 and related kinases was investigated by Western blotting and co-immunoprecipitation in whole hearts and isolated cardiomyocytes from 12 to 14-week diabetic rats. Direct ROCK2 phosphorylation of PKCβ2 was examined in vitro. siRNA silencing was used to confirm role of ROCK2 in PKCβ2 phosphorylation in vascular smooth muscle cells cultured in high glucose. Furthermore, the effect of ROCK inhibition on GLUT4 translocation was determined in isolated cardiomyocytes by confocal microscopy. Results Expression of ROCK2 and expression and phosphorylation of PKCβ2 were increased in diabetic hearts. A physical interaction between the two kinases was demonstrated by reciprocal immunoprecipitation, while ROCK2 directly phosphorylated PKCβ2 at T641 in vitro. ROCK2 siRNA in vascular smooth muscle cells or inhibition of ROCK in diabetic hearts reduced PKCβ2 T641 phosphorylation, and this was associated with attenuation of PKCβ2 activity. PKCβ2 also formed a complex with PDK-1 and its target AKT, and ROCK inhibition resulted in upregulation of the phosphorylation of PDK-1 and AKT, and increased translocation of glucose transporter 4 (GLUT4) to the plasma membrane in diabetic hearts. Conclusion This study demonstrates that over-activation of ROCK2 contributes to diabetic cardiomyopathy by multiple mechanisms, including direct phosphorylation and activation of PKCβ2 and interference with the PDK-1-mediated phosphorylation and activation of AKT and translocation of GLUT4. This suggests that ROCK2 is a critical node in the development of diabetic cardiomyopathy and may be an effective target to improve cardiac function in diabetes.
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Affiliation(s)
- Guorong Lin
- Molecular and Cellular Pharmacology Research Group, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Roger W. Brownsey
- Dept. of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Kathleen M. MacLeod
- Molecular and Cellular Pharmacology Research Group, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
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DeNardo BD, Holloway MP, Ji Q, Nguyen KT, Cheng Y, Valentine MB, Salomon A, Altura RA. Quantitative phosphoproteomic analysis identifies activation of the RET and IGF-1R/IR signaling pathways in neuroblastoma. PLoS One 2013; 8:e82513. [PMID: 24349301 PMCID: PMC3859635 DOI: 10.1371/journal.pone.0082513] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/24/2013] [Indexed: 12/20/2022] Open
Abstract
Neuroblastoma is an embryonal tumor of childhood with a heterogenous clinical presentation that reflects differences in activation of complex biological signaling pathways. Protein phosphorylation is a key component of cellular signal transduction and plays a critical role in processes that control cancer cell growth and survival. We used shotgun LC/MS to compare phosphorylation between a human MYCN amplified neuroblastoma cell line (NB10), modeling a resistant tumor, and a human neural precursor cell line (NPC), modeling a normal baseline neural crest cell. 2181 unique phosphorylation sites representing 1171 proteins and 2598 phosphopeptides were found. Protein kinases accounted for 6% of the proteome, with a predominance of tyrosine kinases, supporting their prominent role in oncogenic signaling pathways. Highly abundant receptor tyrosine kinase (RTK) phosphopeptides in the NB10 cell line relative to the NPC cell line included RET, insulin-like growth factor 1 receptor/insulin receptor (IGF-1R/IR), and fibroblast growth factor receptor 1 (FGFR1). Multiple phosphorylated peptides from downstream mediators of the PI3K/AKT/mTOR and RAS pathways were also highly abundant in NB10 relative to NPC. Our analysis highlights the importance of RET, IGF-1R/IR and FGFR1 as RTKs in neuroblastoma and suggests a methodology that can be used to identify potential novel biological therapeutic targets. Furthermore, application of this previously unexploited technology in the clinic opens the possibility of providing a new wide-scale molecular signature to assess disease progression and prognosis.
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Affiliation(s)
- Bradley D. DeNardo
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, The Warren Albert School of Medicine at Brown University, Providence, Rhode Island, United States of America
| | - Michael P. Holloway
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, The Warren Albert School of Medicine at Brown University, Providence, Rhode Island, United States of America
| | - Qinqin Ji
- Department of Chemistry, Brown University, Providence, Rhode Island, United States of America
| | - Kevin T. Nguyen
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, The Warren Albert School of Medicine at Brown University, Providence, Rhode Island, United States of America
| | - Yan Cheng
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, The Warren Albert School of Medicine at Brown University, Providence, Rhode Island, United States of America
| | - Marcus B. Valentine
- St. Jude Comprehensive Cancer Center Cytogenetic Shared Resource, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Arthur Salomon
- Department of Molecular and Cellular Biochemistry, Brown University, Providence, Rhode Island, United States of America
| | - Rachel A. Altura
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, The Warren Albert School of Medicine at Brown University, Providence, Rhode Island, United States of America
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Fyffe C, Falasca M. 3-Phosphoinositide-dependent protein kinase-1 as an emerging target in the management of breast cancer. Cancer Manag Res 2013; 5:271-80. [PMID: 24039447 PMCID: PMC3771848 DOI: 10.2147/cmar.s35026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It should be noted that 3-phosphoinositide-dependent protein kinase-1 (PDK1) is a protein encoded by the PDPK1 gene, which plays a key role in the signaling pathways activated by several growth factors and hormones. PDK1 is a crucial kinase that functions downstream of phosphoinositide 3-kinase activation and activates members of the AGC family of protein kinases, such as protein kinase B (Akt), protein kinase C (PKC), p70 ribosomal protein S6 kinases, and serum glucocorticoid-dependent kinase, by phosphorylating serine/threonine residues in the activation loop. AGC kinases are known to play crucial roles in regulating physiological processes relevant to metabolism, growth, proliferation, and survival. Changes in the expression and activity of PDK1 and several AGC kinases have been linked to human diseases including cancer. Recent data have revealed that the alteration of PDK1 is a critical component of oncogenic phosphoinositide 3-kinase signaling in breast cancer, suggesting that inhibition of PDK1 can inhibit breast cancer progression. Indeed, PDK1 is highly expressed in a majority of human breast cancer cell lines and both PDK1 protein and messenger ribonucleic acid are overexpressed in a majority of human breast cancers. Furthermore, overexpression of PDK1 is sufficient to transform mammary epithelial cells. PDK1 plays an essential role in regulating cell migration, especially in the context of phosphatase and tensin homologue deficiency. More importantly, downregulation of PDK1 levels inhibits migration and experimental metastasis of human breast cancer cells. Thus, targeting PDK1 may be a valuable anticancer strategy that may improve the efficacy of chemotherapeutic strategies in breast cancer patients. In this review, we summarize the evidence that has been reported to support the idea that PDK1 may be a key target in breast cancer management.
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Affiliation(s)
- Chanse Fyffe
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Inositide Signallling Group, London, UK
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Li J, Wu F, Sheng F, Li YJ, Jin D, Ding X, Zhang S. NOK/STYK1 interacts with GSK-3β and mediates Ser9 phosphorylation through activated Akt. FEBS Lett 2012; 586:3787-92. [DOI: 10.1016/j.febslet.2012.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/15/2012] [Accepted: 09/05/2012] [Indexed: 11/16/2022]
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Zhong Y, Huang Y, Cao J, Lu X, Feng M, Shen G, Shen A, Yu X. Increase in phosphorylation of PDK1 and cell survival after acute spinal cord injury. J Neurol Sci 2012; 320:38-44. [DOI: 10.1016/j.jns.2012.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 02/23/2012] [Accepted: 03/01/2012] [Indexed: 11/30/2022]
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Zhong Y, Huang Y, Cao J, Lu X, Feng M, Shen G, Shen A, Yu X. WITHDRAWN: Increase in phosphorylation of PDK1 and cell survival after acute spinal cord injury. J Neurol Sci 2012:S0022-510X(12)00441-8. [PMID: 22947897 DOI: 10.1016/j.jns.2012.02.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 02/23/2012] [Accepted: 02/29/2012] [Indexed: 11/22/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.jns.2012.06.003. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Yi Zhong
- Department of Orthopaedics, The Second Affiliated Hospital, Nanjing Medical University, Nanjing 210011, China
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Cardioprotective effects of 3-phosphoinositide-dependent protein kinase-1 on hypoxic injury in cultured neonatal rat cardiomyocytes and myocardium in a rat myocardial infarct model. Biosci Biotechnol Biochem 2012; 76:101-7. [PMID: 22232248 DOI: 10.1271/bbb.110562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) is involved in numerous cellular responses. In this study, we investigated the protective effects of PDK1 gene expression against hypoxic conditions in cultured rat CMCs (rCMCs) and in a rat myocardial infarction (MI) model using the lentiviral vector (LeV) system. LeV-PDK1 transfer effectively reduced the apoptotic cell death caused by hypoxic injury as compared to LeV-GFP transfer in rCMCs the expression of survival proteins increased in the LeV-PDK1 group, whereas apoptosis signaling decreased in the rCMCs and in infarcted hearts treated with LeV-PDK1. LeV-PDK1 transfer also reduced apoptosis and infarct size and attenuated myocardial wall thinning and ventricular remodeling in a rat MI model. These findings suggest that PDK1 has a protective role in the injured ischemic myocardium via overexpression of the cell survival pathway in CMCs. Hence PDK1 can be used as a treatment strategy for myocardial salvage inin hypoxic injury.
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Lucas N, Cho W. Phosphatidylserine binding is essential for plasma membrane recruitment and signaling function of 3-phosphoinositide-dependent kinase-1. J Biol Chem 2011; 286:41265-41272. [PMID: 21971045 DOI: 10.1074/jbc.m111.300806] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
3-Phosphoinositide-dependent kinase-1 (PDK1) is a ubiquitously expressed serine/threonine kinase that functions downstream of phosphoinositide 3-kinase. Although binding of 3'-phosphoinositides, phosphatidylinositol 3,4,5-trisphosphate and phosphatidylinositol 3,4-bisphosphate, to the pleckstrin homology (PH) domain of PDK1 is known to be essential for its interaction with and activation of downstream kinases, the mechanism by which PDK1 is recruited to the plasma membrane remains controversial. Our surface plasmon resonance analysis of the PDK1 PH domain and selected mutants shows that the PH domain specifically binds phosphatidylserine using a site that is separate from the canonical phosphoinositide-binding site. Further cell studies show that this specific phosphatidylserine binding is important for the plasma membrane localization and signaling function of PDK1.
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Affiliation(s)
- Nathan Lucas
- Department of Chemistry, University of Illinois, Chicago, Illinois 60607
| | - Wonhwa Cho
- Department of Chemistry, University of Illinois, Chicago, Illinois 60607.
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Hofler A, Nichols T, Grant S, Lingardo L, Esposito EA, Gridley S, Murphy ST, Kath JC, Cronin CN, Kraus M, Alton G, Xie Z, Sutton S, Gehring M, Ermolieff J. Study of the PDK1/AKT signaling pathway using selective PDK1 inhibitors, HCS, and enhanced biochemical assays. Anal Biochem 2011; 414:179-86. [PMID: 21402045 DOI: 10.1016/j.ab.2011.03.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 02/21/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
The PI3K/AKT signaling pathway has an important regulatory role in cancer cell growth and tumorigenesis. Signal transduction through this pathway requires the assembly and activation of PDK1 and AKT at the plasma membrane. On activation of the pathway, PDK1 and AKT1/2 translocate to the membrane and bind to phosphatidylinositol-(3,4,5)-trisphosphate (PIP(3)) through interaction with their pleckstrin-homology domains. A biochemical method was developed to measure the kinase activity of PDK1 and AKT1/2, utilizing nickel-chelating coated lipid vesicles as a way to mimic the membrane environment. The presence of these vesicles in the reaction buffer enhanced the specific activity of the His-tagged PDK1 (full-length, and the truncated kinase domain) and the activity of the full-length His-tagged AKT1 and AKT2 when assayed in a cascade-type reaction. This enhanced biochemical assay is also suitable for measuring the inhibition of PDK1 by several selective compounds from the carbonyl-4-amino-pyrrolopyrimidine (CAP) series. One of these inhibitors, PF-5168899, was further evaluated using a high content cell-based assay in the presence of CHO cells engineered with GFP-PDK1.
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Affiliation(s)
- Alexandra Hofler
- Department of Oncology, Pfizer, 10578 Science Center Drive, San Diego, CA 92121, USA
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Bayascas JR. PDK1: the major transducer of PI 3-kinase actions. Curr Top Microbiol Immunol 2011; 346:9-29. [PMID: 20563709 DOI: 10.1007/82_2010_43] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Most of the cellular responses to phosphatidylinositol 3-kinase activation and phosphatidylinositol 3,4,5-trisphosphate production are mediated by the activation of a group of AGC kinases comprising PKB, S6K, RSK, SGK and PKC isoforms, which play essential roles in regulating physiological processes related to cell growth, proliferation, survival and metabolism. All these growth-factor-stimulated AGC kinases possess a common upstream activator, namely PDK1, a master kinase, which, being constitutively active, is still able to phosphorylate and activate its AGC substrates in response to rises in the levels of the PtdIns(3,4,5)P(3) second messenger. In this chapter, the biochemical, structural and genetic data on the mechanism of action and physiological roles of PDK1 are reviewed, and its potential as a pharmaceutical target for the design of drugs therapeutically beneficial to treat human disease such us diabetes and cancer is discussed.
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Affiliation(s)
- José Ramón Bayascas
- Institut de Neurociències & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain.
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Li Y, Yang KJ, Park J. Multiple implications of 3-phosphoinositide-dependent protein kinase 1 in human cancer. World J Biol Chem 2010; 1:239-47. [PMID: 21537480 PMCID: PMC3083972 DOI: 10.4331/wjbc.v1.i8.239] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/13/2010] [Accepted: 07/20/2010] [Indexed: 02/05/2023] Open
Abstract
3-phosphoinositide-dependent protein kinase-1 (PDK1) is a central mediator of cellular signaling between phosphoinositide-3 kinase and various intracellular serine/threonine kinases, including protein kinase B, p70 ribosomal S6 kinase, serum and glucocorticoid-inducible kinase, and protein kinase C. PDK1 activates members of the AGC family of protein kinases by phosphorylating serine/threonine residues in the activation loop. Here, we review the regulatory mechanisms of PDK1 and its roles in cancer. PDK1 is activated by autophosphorylation in the activation loop and other serine residues, as well as by phosphorylation of Tyr-9 and Tyr-373/376. Src appears to recognize PDK1 following tyrosine phosphorylation. The role of heat shock protein 90 in regulating PDK1 stability and PDK1-Src complex formation are also discussed. Furthermore, we summarize the subcellular distribution of PDK1. Finally, an important role for PDK1 in cancer chemotherapy is proposed. In conclusion, a better understanding of its molecular regulatory mechanisms in various signaling pathways will help to explain how PDK1 acts as an oncogenic kinase in various cancers, and will contribute to the development of novel cancer chemotherapies.
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Affiliation(s)
- Yuwen Li
- Yuwen Li, Keum-Jin Yang, Jongsun Park, Department of Pharmacology, Metabolic Diseases and Cell Signaling Laboratory, Cancer Research Institute, Research Institute for Medical Sciences, College of Medicine, Chungnam National University, Daejeon 301-131, South Korea
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Dwivedi Y, Rizavi HS, Zhang H, Roberts RC, Conley RR, Pandey GN. Modulation in activation and expression of phosphatase and tensin homolog on chromosome ten, Akt1, and 3-phosphoinositide-dependent kinase 1: further evidence demonstrating altered phosphoinositide 3-kinase signaling in postmortem brain of suicide subjects. Biol Psychiatry 2010; 67:1017-25. [PMID: 20163786 PMCID: PMC2868089 DOI: 10.1016/j.biopsych.2009.12.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 12/02/2009] [Accepted: 12/06/2009] [Indexed: 12/15/2022]
Abstract
BACKGROUND Phosphoinositide 3-kinase (PI3-K) signaling plays a crucial role in neuronal growth and plasticity. Recently, we demonstrated that suicide brain is associated with decreased activation and expression of selective catalytic and regulatory subunits of PI3-K. The present investigation examined the regulation and functional significance of compromised PI3-K in suicide brain at the level of upstream phosphatase and tensin homologue on chromosome ten (PTEN) and downstream substrates 3-phosphoinositide-dependent kinase 1 (PDK1) and Akt. METHODS Messenger RNA expression of Akt1, Akt3, PTEN, and PDK1 by competitive reverse transcription polymerase polymerase chain reaction; protein expression of Akt1, Akt3, PTEN, PDK1, phosphorylated Akt1 (Ser473 and Thr308), phosphorylated PDK1, and phosphorylated PTEN by Western blot; and catalytic activities of Akt1, Akt3, and PDK1 by enzymatic assays were determined in prefrontal cortex and hippocampus obtained from suicide subjects and nonpsychiatric control subjects. RESULTS No significant changes in the expression of Akt1 or Akt3 were observed; however, catalytic activity of Akt1, but not of Akt3, was decreased in prefrontal cortex and hippocampus of suicide subjects, which was associated with decreased phosphorylation of Akt1 at Ser473 and Thr308. The catalytic activity of PDK1 and the level of phosphorylated PDK1 were also decreased in both brain areas without any change in expression levels of PDK1. On the other hand, messenger RNA and protein expression of PTEN was increased, whereas the level of phosphorylated PTEN was decreased. CONCLUSIONS Our study demonstrates abnormalities in PI3-K signaling at several levels in brain of suicide subjects and suggests the possible involvement of aberrant PI3-K/Akt signaling in the pathogenic mechanisms of suicide.
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Affiliation(s)
- Yogesh Dwivedi
- Department of Psychiatry, Psychiatric Institute, University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Hooriyah S. Rizavi
- Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago IL, 60612, USA
| | - Hui Zhang
- Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago IL, 60612, USA
| | - Rosalinda C. Roberts
- Department of Psychiatry, University of Alabama at Birmingham, 1530 3rd Ave, Birmingham, AL, 35294, USA
| | | | - Ghanshyam N. Pandey
- Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago IL, 60612, USA
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Alberobello AT, D'Esposito V, Marasco D, Doti N, Ruvo M, Bianco R, Tortora G, Esposito I, Fiory F, Miele C, Beguinot F, Formisano P. Selective disruption of insulin-like growth factor-1 (IGF-1) signaling via phosphoinositide-dependent kinase-1 prevents the protective effect of IGF-1 on human cancer cell death. J Biol Chem 2009; 285:6563-72. [PMID: 20044479 DOI: 10.1074/jbc.m109.097410] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Insulin-like growth factor-1 (IGF-1) signaling system exerts a broad antiapoptotic function and plays a crucial role in resistance to anticancer therapies. Exposure of MCF-7 breast cancer cells to IGF-1 rapidly and transiently induced tyrosine phosphorylation and activation of phosphoinositide-dependent kinase-1 (PDK1). This was paralleled by Akt/protein kinase B and protein kinase C-zeta phosphorylation, at Thr(308) and Thr(410), respectively. IGF-1 treatment also enhanced PDK1 interaction with IGF-1 receptor (IGF-1R) in intact MCF-7 cells. Pulldown assays revealed that PDK1 bound IGF-1R in vitro and that the region encompassing amino acids 51-359 of PDK1 was necessary for the interaction. Synthetic peptides corresponding to IGF-1R C terminus amino acids 1295-1337 (C43) and to PDK1 amino acids 114-141 reduced in vitro IGF-1R/PDK1 interaction in a concentration-dependent manner. Loading of fluoresceinated-C43 (fluorescein isothiocyanate (FITC)-C43) into MCF-7 cells significantly reduced IGF-1R/PDK1 interaction and phosphorylation of PDK1 substrates. Moreover, FITC-C43 intracellular loading reverted the protective effect of IGF-1 on growth factor deprivation-induced cell death. Finally, the inhibition of IGF-1R/PDK1 interaction and signaling by FITC-C43 was accompanied by 2-fold enhanced killing capacity of cetuximab in human GEO colon adenocarcinoma cells and was sufficient to restore cell death in cetuximab-resistant cell clones. Thus, disruption of PDK1 interaction with IGF-1R reduces IGF-1 survival effects in cancer cells and may enhance cell death by anticancer agents.
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Affiliation(s)
- A Teresa Alberobello
- Dipartimento di Biologia e Patologia Cellulare e Molecolare and Istituto di Endocrinologia ed Oncologia Sperimentale del Consiglio Nazionale delle Ricerche, Università di Napoli Federico II, 80131 Naples, Italy
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Lopez-Bergami P, Kim H, Dewing A, Goydos J, Aaronson S, Ronai Z. c-Jun regulates phosphoinositide-dependent kinase 1 transcription: implication for Akt and protein kinase C activities and melanoma tumorigenesis. J Biol Chem 2009; 285:903-13. [PMID: 19910471 DOI: 10.1074/jbc.m109.075630] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mutations in N-RAS and B-RAF, which commonly occur in melanomas, result in constitutive activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) signaling. Active ERK increases expression and activity of the c-Jun transcription factor, linking ERK and Jun N-terminal kinase (JNK) cascades. Here, we show that c-Jun regulates transcription of phosphoinositide-dependent kinase 1 (PDK1) with a concomitant impact on Akt and protein kinase C (PKC) activity and related substrates. Inhibition of c-Jun reduces PDK1 expression and attenuates Akt and PKC activity, which can be restored by exogenous PDK1. c-Jun regulation of PDK1 in melanoma contributes to growth rate and the ability to form tumors in mice. Correspondingly, increased levels of c-Jun in melanoma cell lines coincide with up-regulation of PDK1 and phosphorylation of PKC and Akt. The identification of c-Jun as a transcriptional regulator of PDK1 expression highlights key mechanisms underlying c-Jun oncogenic activity, and provides new insight into the nature of up-regulated Akt and PKC in melanoma.
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Affiliation(s)
- Pablo Lopez-Bergami
- Signal Transduction Program, The Burnham Institute for Medical Research, La Jolla, California 92037, USA
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36
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Abstract
The activation of PI3K (phosphoinositide 3-kinase) family members is a universal event in response to virtually all cytokines, growth factors and hormones. As a result of formation of PtdIns with an added phosphate at the 3 position of the inositol ring, activation of the protein kinases PDK1 (phosphoinositide-dependent kinase 1) and PKB (protein kinase B)/Akt occurs. The PI3K/PKB pathway impinges upon a remarkable array of intracellular events that influence either directly or indirectly whether or not a cell will undergo apoptosis. In this review, the many ways in which PI3K/PKB can control these processes are summarized. Not all of the events described will necessarily play a role in any one cell type, but a subset of these events is probably essential for the survival of every cell.
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Roztocil E, Nicholl SM, Davies MG. Mechanisms of sphingosine-1-phosphate-induced akt-dependent smooth muscle cell migration. Surgery 2008; 145:34-41. [PMID: 19081473 DOI: 10.1016/j.surg.2008.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 08/04/2008] [Indexed: 11/16/2022]
Abstract
BACKGROUND Sphingosine-1-phosphate (S-1-P) is a bioactive sphingolipid released from activated platelets that stimulates migration of vascular smooth muscle cells (VSMC) in vitro. S-1-P will activate akt, which can regulate multiple cellular functions including cell migration. Akt activation is downstream of phosphatidylinositol 3'-kinase (PI3-K) and phosphoinositide-dependent protein kinase-1 (PDK1). The objective of this study was to examine the regulation of akt signaling during smooth muscle cell (SMC) migration in response to S-1-P. METHODS Murine arterial SMC were cultured in vitro. Linear wound and microchemotaxis assays of migration in Boyden chambers were performed in the presence of S-1-P with and without an akt inhibitor (aktI). Assays were performed for PI3-K, PDK1, akt, and GSK3beta in the presence of various inhibitors and after transfection with the G beta gamma inhibitor beta ARK(CT). RESULTS S-1-P induced time-dependent PI3-K, PDK1, and akt activation. The migratory responses in both assays to S-1-P were blocked by aktI. Activation of akt and dephosphorylation of its downstream kinase, GSK3 beta, were inhibited by aktI. Inhibition of PI3-K with LY294002 significantly decreased activation of both PI3-K and akt. Inhibition of G beta gamma inhibited akt activation through a decrease in activation of both PI3-K and PDK1. Although inhibition of the ras with manumycin A had no effect, inhibition of rho with C3 limited activation of both PI3K and akt. PDK1 responses were unchanged by inhibition of GTPases. Inhibiting the generation of reactive oxygen species with N-acetylcysteine and of epidermal growth factor receptor with AG1478 inhibited PDK1 activation in response to S-1-P. CONCLUSION S-1-P-mediated migration is akt-dependent. S-1-P-mediated akt phosphorylation is controlled by a G beta gamma-dependent PI3-K activation, which requires the GTPase rho and G beta gamma. PDK1 activation requires G beta gamma-dependent generation of reactive oxygen species and epidermal growth factor receptor activation.
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Affiliation(s)
- Elisa Roztocil
- Department of Cardiovascular Surgery, Methodist DeBakey Heart and Vascular Center, The Methodist Hospital, Houston, TX 77030, USA
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38
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Mutations in the catalytic subunit of class IA PI3K confer leukemogenic potential to hematopoietic cells. Oncogene 2008; 27:4096-106. [DOI: 10.1038/onc.2008.40] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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3-Hydroxyanthranilic acid inhibits PDK1 activation and suppresses experimental asthma by inducing T cell apoptosis. Proc Natl Acad Sci U S A 2007; 104:18619-24. [PMID: 18003900 DOI: 10.1073/pnas.0709261104] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
3-Hydroxyanthranilic acid (HAA), a compound generated during tryptophan metabolism initiated by indoleamine 2,3-dioxygenase, is known to induce T cell death, but its molecular target is not known. Here we report that HAA inhibits NF-kappaB activation upon T cell antigen receptor engagement by specifically targeting PDK1. Inhibition of NF-kappaB by HAA leads to dysfunction and cell death of activated Th2 cells, which in turn suppresses experimental asthma. Inhibition of NF-kappaB and induction of apoptosis is specific to CD4 T cells because HAA does not inhibit NF-kappaB activation or induce cell death upon Toll-like receptor 4 stimulation in dendritic cells. Thus, HAA is a natural inhibitor that restrains T cell expansion and activation.
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Tsokas P, Ma T, Iyengar R, Landau EM, Blitzer RD. Mitogen-activated protein kinase upregulates the dendritic translation machinery in long-term potentiation by controlling the mammalian target of rapamycin pathway. J Neurosci 2007; 27:5885-94. [PMID: 17537959 PMCID: PMC6672260 DOI: 10.1523/jneurosci.4548-06.2007] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Protein synthesis is required for persistent forms of synaptic plasticity, including long-term potentiation (LTP). A key regulator of LTP-related protein synthesis is mammalian target of rapamycin (mTOR), which is thought to modulate translational capacity by facilitating the synthesis of particular components of the protein synthesis machinery. Recently, extracellularly regulated kinase (ERK) also was shown to mediate plasticity-related translation, an effect that may involve regulation of the mTOR pathway. We studied the interaction between the mTOR and ERK pathways in hippocampal LTP induced at CA3-CA1 synapses by high-frequency synaptic stimulation (HFS). Within minutes after HFS, the expression of multiple translational proteins, the synthesis of which is under the control of mTOR, increased in area CA1 stratum radiatum. This upregulation was detected in pyramidal cell dendrites and was blocked by inhibitors of the ERK pathway. In addition, ERK mediated the stimulation of mTOR by HFS. The possibility that ERK regulates mTOR by acting at a component further upstream in the phosphatidylinositide 3-kinase (PI3K)-mTOR pathway was tested by probing the phosphorylation of p90-S6 kinase, phosphoinositide-dependent kinase 1 (PDK1), and Akt. ERK inhibitors blocked HFS-induced phosphorylation of all three proteins at sites implicated in the regulation of mTOR. Moreover, a component of basal and HFS-induced ERK activity depended on PI3K, indicating that mTOR-mediated protein synthesis in LTP requires coincident and mutually dependent activity in the PI3K and ERK pathways. The role of ERK in regulating PDK1 and Akt, with their extensive effects on cellular function, has important implications for the coordinated response of the neuron to LTP-inducing stimulation.
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Affiliation(s)
| | - Tao Ma
- Departments of Pharmacology and Biological Chemistry and
| | - Ravi Iyengar
- Departments of Pharmacology and Biological Chemistry and
| | - Emmanuel M. Landau
- Departments of Pharmacology and Biological Chemistry and
- Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, and
- Psychiatry Service, Bronx Veterans Administration Medical Center, Bronx, New York 10463
| | - Robert D. Blitzer
- Departments of Pharmacology and Biological Chemistry and
- Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, and
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Liu Y, Zhu M, Nishida K, Hirano T, Zhang W. An essential role for RasGRP1 in mast cell function and IgE-mediated allergic response. ACTA ACUST UNITED AC 2006; 204:93-103. [PMID: 17190838 PMCID: PMC2118421 DOI: 10.1084/jem.20061598] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cross-linking of the FcepsilonRI activates the phosphatidyl inositol 3 kinase (PI3K) and mitogen-activated protein kinase pathways. Previous studies demonstrate that Ras guanyl nucleotide-releasing protein (RasGRP)1 is essential in T cell receptor-mediated Ras-Erk activation. Here, we report that RasGRP1 plays an important role in FcepsilonRI-mediated PI3K activation and mast cell function. RasGRP1-deficient mice failed to mount anaphylactic allergic reactions. RasGRP1-/- mast cells had markedly reduced degranulation and cytokine production. Although FcepsilonRI-mediated Erk activation was normal, PI3K activation was diminished. Consequently, activation of Akt, PIP3-dependent kinase, and protein kinase C delta was defective. Expression of a constitutively active form of N-Ras could rescue the degranulation defect and Akt activation. We further demonstrated that RasGRP1-/- mast cells were defective in granule translocation, microtubule formation, and RhoA activation. Our results identified RasGRP1 as an essential regulator of mast cell function.
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Affiliation(s)
- Yan Liu
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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Budas GR, Sukhodub A, Alessi DR, Jovanović A. 3'Phosphoinositide-dependent kinase-1 is essential for ischemic preconditioning of the myocardium. FASEB J 2006; 20:2556-8. [PMID: 17077284 PMCID: PMC2128707 DOI: 10.1096/fj.06-6252fje] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Brief periods of ischemia and reperfusion that precede sustained ischemia lead to a reduction in myocardial infarct size. This phenomenon, known as ischemic preconditioning, is mediated by signaling pathway(s) that are yet to be fully defined. 3'-Phosphoinositide-dependent kinase-1 (PDK1) has been implicated in numerous cellular processes. However, the involvement of PDK1 in preconditioning has yet to be elucidated. Studying PDK1 is not as straightforward as it is for the majority of kinases, due to the lack of a specific inhibitor of PDK1. Therefore, we have taken advantage of PDK1 hypomorphic mutant mice with reduced expression of PDK1 to study the role of PDK1 in preconditioning. Whole heart and single cell models of preconditioning demonstrated that the hearts and cardiac cells from PDK1 hypomorphic mice could not be preconditioned. The cardioprotective effect of PDK1 was not related to the effect that preconditioning has on sarcolemmal membrane action potential as revealed by di-8-ANEPPS, a sarcolemmal-potential sensitive dye, and laser confocal microscopy. In contrast, experiments with JC-1, a mitochondrial membrane potential-sensitive dye, has demonstrated that intact PDK1 levels were required for preconditioning-mediated regulation of mitochondrial membrane potential. Western blotting combined with functional experiments have shown that intact PDK1 levels were required for preconditioning-induced phosphorylation of protein kinase B (PKB), glycogen synthase kinase-3beta (GSK-3beta), and cardioprotection. We conclude that PDK1 mediates preconditioning in the heart by regulating activating PKB-GSK-3beta to regulate mitochondrial but not sarcolemmal membrane potential. 3'Phosphoinositide-dependent kinase-1 (PDK1) is essential for ischemic preconditioning of the myocardium.
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Affiliation(s)
- Grant R. Budas
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, UK
| | - Andrey Sukhodub
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, UK
| | - Dario R. Alessi
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Aleksandar Jovanović
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, UK
- Correspondence: Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK. E-mail:
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Gao X, Harris TK. Role of the PH domain in regulating in vitro autophosphorylation events required for reconstitution of PDK1 catalytic activity. Bioorg Chem 2006; 34:200-23. [PMID: 16780920 DOI: 10.1016/j.bioorg.2006.05.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2006] [Accepted: 05/09/2006] [Indexed: 01/17/2023]
Abstract
In addition to its catalytic domain, phosphoinsositide-dependent protein kinase-1 (PDK1) contains a C-terminal pleckstrin homology (PH) domain, which binds the membrane-bound phosphatidylinositol (3,4,5)-triphosphate [PI(3,4,5)P3] second messenger. Here, we report in vitro kinetic, phosphopeptide mapping, and oligomerization studies that address the role of the PH domain in regulating specific autophosphorylation events, which are required for PDK1 catalytic activation. First, 'inactive' unphosphorylated forms of N-terminal His6 tagged full length (His6-PDK1) and catalytic domain constructs [His6-PDK1(Delta PH)] were generated by treatment with Lambda protein phosphatase (lambda PP). Reconstitution of lambda PP-treated His6-PDK1(Delta PH) catalytic activity required activation loop Ser-241 phosphorylation, which occurred only upon trans-addition of 'active' PDK1 with an apparent bimolecular rate constant of (app)k1(S241) = 374+/-29 M(-1) s(-1). In contrast, full length lambda PP-treated His6-PDK1 catalyzed Ser-241 cis-autophosphorylation with an apparent first-order rate constant of (app)k1(S241) = (5.0+/-1.5) x 10(-4) s(-1) but remained 'inactive'. Reconstitution of lambda PP-treated His(6)-PDK1 catalytic activity occurred only when autophosphorylated in the presence of PI(3,4,5)P3 containing vesicles. PI(3,4,5)P3 binding to the PH domain activated apparent first-order Ser-241 autophosphorylation by 20-fold [(app)k1(S241) = (1.1+/-0.1) x 10(-2) s(-1)] and also promoted biphasic Thr-513 trans-autophosphorylation [(app)k2(T513) = (4.9+/-1.1) x 10(2) M(-1) s(-1) and(app)k3(T513) = (1.5+/-0.2) x 10(3) M(-1) s(-1)]. The results of mutagenesis studies suggest that Thr-513 phosphorylation may cause dissociation of autoinhibitory contacts formed between the contiguous regulatory PH and catalytic kinase domains.
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Affiliation(s)
- Xinxin Gao
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, P.O. Box 016129, Miami, FL 33101-6129, USA
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Riojas RA, Kikani CK, Wang C, Mao X, Zhou L, Langlais PR, Hu D, Roberts JL, Dong LQ, Liu F. Fine tuning PDK1 activity by phosphorylation at Ser163. J Biol Chem 2006; 281:21588-21593. [PMID: 16751192 DOI: 10.1074/jbc.m600393200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) mediates phosphorylation and activation of members of the AGC protein kinase family and plays an essential role in insulin signaling and action. However, whether and how PDK1 activity is regulated in cells remains largely uncharacterized. In the present study, we show that PDK1 undergoes insulin-stimulated and phosphatidylinositol 3-kinase-dependent phosphorylation at Ser244 in the activation loop and at a novel site: Ser163 in the hinge region between the two lobes of the kinase domain. Sequence alignment studies revealed that the residue corresponding to Ser163 of PDK1 in all other AGC kinases is glutamate, suggesting that a negative charge at this site may be important for PDK1 function. Replacing Ser163 with a negatively charged residue, glutamate, led to a 2-fold increase in PDK1 activity. Molecular modeling studies suggested that phosphorylated Ser163 may form additional hydrogen bonds with Tyr149 and Gln223. In support of this, mutation of Tyr149 to Ala is sufficient to reduce PDK1 activity. Taken together, our results suggest that PDK1 phosphorylation of Ser163 may provide a mechanism to fine-tune PDK1 activity and function in cells.
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Affiliation(s)
- Ramon A Riojas
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Chintan K Kikani
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Changhua Wang
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Xuming Mao
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Lijun Zhou
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Paul R Langlais
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Derong Hu
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - James L Roberts
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229; Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Lily Q Dong
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229; Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229; Departments of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Feng Liu
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229; Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229; Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229.
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Oda K, Kitano H. A comprehensive map of the toll-like receptor signaling network. Mol Syst Biol 2006; 2:2006.0015. [PMID: 16738560 PMCID: PMC1681489 DOI: 10.1038/msb4100057] [Citation(s) in RCA: 242] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Accepted: 02/23/2006] [Indexed: 12/18/2022] Open
Abstract
Recognition of pathogen-associated molecular signatures is critically important in proper activation of the immune system. The toll-like receptor (TLR) signaling network is responsible for innate immune response. In mammalians, there are 11 TLRs that recognize a variety of ligands from pathogens to trigger immunological responses. In this paper, we present a comprehensive map of TLRs and interleukin 1 receptor signaling networks based on papers published so far. The map illustrates the possible existence of a main network subsystem that has a bow-tie structure in which myeloid differentiation primary response gene 88 (MyD88) is a nonredundant core element, two collateral subsystems with small GTPase and phosphatidylinositol signaling, and MyD88-independent pathway. There is extensive crosstalk between the main bow-tie network and subsystems, as well as feedback and feedforward controls. One obvious feature of this network is the fragility against removal of the nonredundant core element, which is MyD88, and involvement of collateral subsystems for generating different reactions and gene expressions for different stimuli.
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Affiliation(s)
- Kanae Oda
- The Systems Biology Institute, Tokyo, Japan
- Department of Fundamental Science and Technology, Keio University, Tokyo, Japan
| | - Hiroaki Kitano
- The Systems Biology Institute, Tokyo, Japan
- Department of Fundamental Science and Technology, Keio University, Tokyo, Japan
- Sony Computer Science Laboratories Inc., Tokyo, Japan
- The Systems Biology Institute, Suite 6A, M31 6-31-15 Jingumae, Shibuya, Tokyo 150-0001, Japan. Tel.: +81 3 5468 1661; Fax: +81 3 5468 1664; E-mail:
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Cariou B, van Harmelen K, Duran-Sandoval D, van Dijk TH, Grefhorst A, Abdelkarim M, Caron S, Torpier G, Fruchart JC, Gonzalez FJ, Kuipers F, Staels B. The farnesoid X receptor modulates adiposity and peripheral insulin sensitivity in mice. J Biol Chem 2006; 281:11039-49. [PMID: 16446356 DOI: 10.1074/jbc.m510258200] [Citation(s) in RCA: 411] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The farnesoid X receptor (FXR) is a bile acid (BA)-activated nuclear receptor that plays a major role in the regulation of BA and lipid metabolism. Recently, several studies have suggested a potential role of FXR in the control of hepatic carbohydrate metabolism, but its contribution to the maintenance of peripheral glucose homeostasis remains to be established. FXR-deficient mice display decreased adipose tissue mass, lower serum leptin concentrations, and elevated plasma free fatty acid levels. Glucose and insulin tolerance tests revealed that FXR deficiency is associated with impaired glucose tolerance and insulin resistance. Moreover, whole-body glucose disposal during a hyperinsulinemic euglycemic clamp is decreased in FXR-deficient mice. In parallel, FXR deficiency alters distal insulin signaling, as reflected by decreased insulin-dependent Akt phosphorylation in both white adipose tissue and skeletal muscle. Whereas FXR is not expressed in skeletal muscle, it was detected at a low level in white adipose tissue in vivo and induced during adipocyte differentiation in vitro. Moreover, mouse embryonic fibroblasts derived from FXR-deficient mice displayed impaired adipocyte differentiation, identifying a direct role for FXR in adipocyte function. Treatment of differentiated 3T3-L1 adipocytes with the FXR-specific synthetic agonist GW4064 enhanced insulin signaling and insulin-stimulated glucose uptake. Finally, treatment with GW4064 improved insulin resistance in genetically obese ob/ob mice in vivo. Although the underlying molecular mechanisms remain to be unraveled, these results clearly identify a novel role of FXR in the regulation of peripheral insulin sensitivity and adipocyte function. This unexpected function of FXR opens new perspectives for the treatment of type 2 diabetes.
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Affiliation(s)
- Bertrand Cariou
- Institut Pasteur de Lille, Département d'Athérosclérose, Lille, F-59019, France
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Otterhag L, Gustavsson N, Alsterfjord M, Pical C, Lehrach H, Gobom J, Sommarin M. Arabidopsis PDK1: identification of sites important for activity and downstream phosphorylation of S6 kinase. Biochimie 2005; 88:11-21. [PMID: 16125835 DOI: 10.1016/j.biochi.2005.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 07/21/2005] [Indexed: 01/14/2023]
Abstract
The Arabidopsis thaliana protein kinase AtPDK1 was identified as a homologue of the mammalian 3-phosphoinositide-dependent protein kinase-1 (PDK1), which is involved in a number of physiological processes including cell growth and proliferation. We now show that AtPDK1, expressed in E. coli as a recombinant protein, undergoes autophosphorylation at several sites. Using mass spectrometry, three phosphorylated amino acid residues, Ser-177, Ser-276 and Ser-382, were identified, followed by mutational analyses to reveal their roles. These residues are not conserved in mammalian PDK1s. Mutation of Ser-276 in AtPDK1 to alanine resulted in an enzyme with no detectable autophosphorylation. Autophosphorylation was significantly reduced in the Ser177Ala mutant but was only slightly reduced in the Ser382Ala mutant. Other identified sites of importance for autophosphorylation and/or activity of AtPDK1 were Asp-167, Thr-176, and Thr-211. Sites in the mammalian PDK1 corresponding to Asp-167 and Thr-211 are essential for PDK1 autophosphorylation and activity. Autophosphorylation was absent in the Asp167Ala mutant while the Thr176Ala and The211Ala mutants exhibited very low but detectable autophosphorylation, pointing to both similarity and difference between mammalian and plant enzymes. We also demonstrate that AtS6k2, an A. thaliana homologue to the mammalian S6 kinases, is an in vitro target of AtPDK1. Our data clearly show that Asp-167, Thr-176, Ser-177, Thr-211, and Ser-276 in AtPDK1 are important for the downstream phosphorylation of AtS6k2. The results confirm that AtPDK1, like mammalian PDK1, needs phosphorylation at several sites for full downstream phosphorylation activity. Finally, we investigated A. thaliana 14-3-3 proteins as potential AtPDK1 regulatory proteins and the effect of phospholipids on the AtPDK1 activity. Nine of the 12 14-3-3 isoforms tested enhanced AtPDK1 activity whereas one isoform suppressed the activity. No significant effects on AtPDK1 activity by the various phospholipids (including phosphoinositides) were evident.
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Affiliation(s)
- Lotta Otterhag
- Department of Plant Biochemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden.
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Abstract
Activation of members of the protein kinase AGC (cAMP dependent, cGMP dependent, and protein kinase C) family is regulated primarily by phosphorylation at two sites: a conserved threonine residue in the activation loop and a serine/threonine residue in a hydrophobic motif (HM) near the COOH terminus. Although phosphorylation of these kinases in the activation loop has been found to be mediated by phosphoinositide-dependent protein kinase-1 (PDK1), the kinase(s) that catalyzes AGC kinase phosphorylation in the HM remains uncharacterized. So far, at least 10 kinases have been suggested to function as an HM kinase or the so-called "PDK2," including mitogen-activated protein (MAP) kinase-activated protein kinase-2 (MK2), integrin-linked kinase (ILK), p38 MAP kinase, protein kinase Calpha (PKCalpha), PKCbeta, the NIMA-related kinase-6 (NEK6), the mammalian target of rapamycin (mTOR), the double-stranded DNA-dependent protein kinase (DNK-PK), and the ataxia telangiectasia mutated (ATM) gene product. However, whether any or all of these kinases act as a physiological HM kinase remains to be established. Nonetheless, available data suggest that multiple systems may be used in cells to regulate the activation of the AGC family kinases. It is possible that, unlike activation loop phosphorylation, phosphorylation of the HM site in the different AGC family kinases is mediated by distinct kinases. In addition, phosphorylation of the AGC family kinase at the HM site could be cell type, signaling pathway, and substrate specific. Identification and characterization of the bonafide HM kinase(s) will be essential to verify these hypotheses.
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Affiliation(s)
- Lily Q Dong
- Dept. of Cellular and Structural Biology, Univ. of Texas Health Science Center, San Antonio, TX 78229, USA
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Scheid MP, Parsons M, Woodgett JR. Phosphoinositide-dependent phosphorylation of PDK1 regulates nuclear translocation. Mol Cell Biol 2005; 25:2347-63. [PMID: 15743829 PMCID: PMC1061613 DOI: 10.1128/mcb.25.6.2347-2363.2005] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
3-phosphoinositide-dependent kinase 1 (PDK1) phosphorylates the activation loop of a number of protein serine/threonine kinases of the AGC kinase superfamily, including protein kinase B (PKB; also called Akt), serum and glucocorticoid-induced kinase, protein kinase C isoforms, and the p70 ribosomal S6 kinase. PDK1 contains a carboxyl-terminal pleckstrin homology domain, which targets phosphoinositide lipids at the plasma membrane and is central to the activation of PKB. However, PDK1 subcellular trafficking to other compartments is not well understood. We monitored the posttranslational modifications of PDK1 following insulin-like growth factor 1 stimulation. PDK1 underwent rapid and transient phosphorylation on S396, which was dependent upon plasma membrane localization. Phosphorylation of S396 was necessary for nuclear shuttling of PDK1, possibly through its influence on an adjacent nuclear export sequence. Thus, mitogen-stimulated phosphorylation of PDK1 provides a means for directed PDK1 subcellular trafficking, with potential implications for PDK1 signaling.
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Affiliation(s)
- Michael P Scheid
- University Health Network, Princess Margaret Hospital, Toronto, Ontario, Canada.
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Komander D, Kular G, Deak M, Alessi DR, van Aalten DMF. Role of T-loop phosphorylation in PDK1 activation, stability, and substrate binding. J Biol Chem 2005; 280:18797-802. [PMID: 15741170 DOI: 10.1074/jbc.m500977200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) phosphorylates the T-loop of several AGC (cAMP-dependent, cGMP-dependent, protein kinase C) family protein kinases, resulting in their activation. Previous structural studies have revealed that the alpha C-helix, located in the small lobe of the kinase domain of PDK1, is a key regulatory element, as it links a substrate interacting site termed the hydrophobic motif (HM) pocket with the phosphorylated Ser-241 in the T-loop. In this study we have demonstrated by mutational analysis that interactions between the phosphorylated Ser-241 and the alpha C-helix are not required for PDK1 activity or substrate binding through the HM-pocket but are necessary for PDK1 to be activated or stabilized by a peptide that binds to this site. The structure of an inactive T-loop mutant of PDK1, in which Ser-241 is changed to Ala, was also determined. This structure, together with surface plasmon resonance binding studies, demonstrates that the PDK1(S241A)-inactive mutant possesses an intact HM-pocket as well as an ordered alpha C-helix. These findings reveal that the integrity of the alpha C-helix and HM-pocket in PDK1 is not regulated by T-loop phosphorylation.
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Affiliation(s)
- David Komander
- Division of Biological Chemistry and Molecular Microbiology and MRC Protein Phosphorylation Unit, MSI/WTB Complex, School of Life Sciences, University of Dundee, Scotland.
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