1
|
El Bakri Y, Karthikeyan S, Lai CH, Bakhite EA, Ahmad I, Abdel-Rahman AE, Abuelhassan S, Marae IS, Mohamed SK, Mague JT. New tetrahydroisoquinoline-4-carbonitrile derivatives as potent agents against cyclin-dependent kinases, crystal structures, and computational studies. J Biomol Struct Dyn 2024; 42:5053-5071. [PMID: 38764131 DOI: 10.1080/07391102.2023.2224899] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/07/2023] [Indexed: 05/21/2024]
Abstract
The synthesis of two new hexahydroisoquinoline-4-carbonitrile derivatives (3a and 3b) is reported along with spectroscopic data and their crystal structures. In compound 3a, the intramolecular O-H···O hydrogen bond constraints the acetyl and hydroxyl groups to be syn. In the crystal, inversion dimers are generated by C-H···O hydrogen bonds and are connected into layers parallel to (10-1) by additional C-H···O hydrogen bonds. The layers are stacked with Cl···S contacts 0.17 Å less than the sum of the respective van der Waals radii. The conformation of the compound 3b is partially determined by the intramolecular O-H···O hydrogen bond. A puckering analysis of the tetrahydroisoquinoline unit was performed. In the crystal, O-H···O and C-H···O hydrogen bonds together with C-H···π(ring) interactions form layers parallel to (01-1) which pack with normal van der Waals interactions. To understand the binding efficiency and stability of the title molecules, molecular docking, and 100 ns dynamic simulation analyses were performed with CDK5A1. To rationalize their structure-activity relationship(s), a DFT study at the B3LYP/6-311++G** theoretical level was also done. The 3D Hirshfled surfaces were also taken to investigate the crystal packings of both compounds. In addition, their ADMET properties were explored.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Youness El Bakri
- Department of Theoretical and Applied Chemistry, South Ural State University, Chelyabinsk, Russia
| | - Subramani Karthikeyan
- Division of Physics, school of advanced science, Vellore Institute of Technology, Chennai Campus, Chennai, Tamil Nadu, India
| | - Chin-Hung Lai
- Department of Medical Applied Chemistry, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
| | | | - Iqrar Ahmad
- Department of Pharmaceutical Chemistry, Prof. Ravindra Nikam College of Pharmacy, Gondur, Maharashtra, India
- Division of Computer Aided Drug Design, Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra, India
| | | | | | - Islam S Marae
- Department of Chemistry, Assiut University, Assiut, Egypt
| | - Shaaban K Mohamed
- Chemistry and Environmental Division, Manchester Metropolitan University, Manchester, England
- Chemistry Department, Minia University, El-Minia, Egypt
| | - Joel T Mague
- Department of Chemistry, Tulane University, New Orleans, Los Angeles, USA
| |
Collapse
|
2
|
Heier JL, Boselli DJ, Parker LL. Antibody-free time-resolved terbium luminescence assays designed for cyclin-dependent kinase 5 (CDK5). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.24.590988. [PMID: 38712268 PMCID: PMC11071522 DOI: 10.1101/2024.04.24.590988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Novel time-resolved terbium luminescence assays were developed for CDK5 and CDK2 by designing synthetic substrates which incorporate phospho-inducible terbium sensitizing motifs with kinase substrate consensus sequences. Substrates designed for CDK5 showed no phosphorylation by CDK2, opening the possibility for CDK5-specific assay development for selective drug discovery.
Collapse
|
3
|
Jabeur R, Corbel C, Loyer P, Le Parc A, Le Grand A, Comte A, Bach S, André-Leroux G, Sire O, Ben Mansour H, Le Tilly V. Identification of Novel Compounds Inhibiting the Kinase Activity of the CDK5/p25 Complex via Direct Binding to p25. Biochemistry 2023; 62:1452-1463. [PMID: 37074084 DOI: 10.1021/acs.biochem.2c00691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Tamoxifen, the gold standard drug for endocrine therapy for breast cancer, modulates the phosphorylation status of the TAU protein in Alzheimer's disease by inhibiting CDK5 kinase activity. Its binding to p25 prevents CDK5/p25 complexation and hence a decrease of CDK5 activity. In breast tumors, this complex is involved in the proliferation and survival of cancer cells, as well as in the disease's prognosis. Still, the molecular stability of the CDK5/p25 complex following tamoxifen exposure in this cancer type has not yet been clearly deciphered. Here, we report the functional characterization of CDK5 and its p25 regulatory subunit in the absence and presence of tamoxifen. In addition, two novel inhibitors of the kinase activity of the CDK5/p25 complex are identified, both of which would reduce the risk of recurrence of estrogen receptor-positive (ER+) breast cancers and prevent drawbacks induced by tamoxifen exposure. Accordingly, 6His-CDK5 and 6His-p25 have been expressed and purified. Fluorescence anisotropy measurements have been used to assess that the two proteins do form an active complex, and thermodynamic parameters of their interaction were measured. It was also confirmed that tamoxifen directly binds to p25 and inhibits CDK5 kinase activity. Similar observations were obtained using 4-hydroxytamoxifen, an active metabolized form of tamoxifen. Two novel compounds have been identified here that harbor a benzofuran moiety and were shown to target directly p25, and their bindings resulted in decreased CDK5 kinase activity. This encouraging alternative opens the way to the ensuing chemical optimization of this scaffold. It also promises a more specific therapeutic approach that may both tackle the pathological signaling in breast cancer and provide a potential new drug for Alzheimer's disease.
Collapse
Affiliation(s)
- Riheb Jabeur
- IRDL UMR CNRS 6027, Université Bretagne Sud, 56017 Vannes, France
- Research Unit of Analysis and Process Applied on the Environment─APAE UR17ES32, Higher Institute of Applied Sciences and Technology, Mahdia, University of Monastir, TN5121 Monastir, Tunisia
| | - Caroline Corbel
- IRDL UMR CNRS 6027, Université Bretagne Sud, 56017 Vannes, France
| | - Pascal Loyer
- Univ Rennes, INSERM, INRAE, Institut NuMeCan (Nutrition, Metabolisms and Cancer) UMR-A 1341, UMR-S 1241, F-35000 Rennes, France
| | | | | | - Arnaud Comte
- Compound Library, ICBMS UMR 5246 CNRS-Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne, France
| | - Stéphane Bach
- Sorbonne Université, CNRS, UMR8227, Integrative Biology of Marine Models Laboratory (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
- Sorbonne Université, CNRS, FR2424, Plateforme de criblage KISSf (Kinase Inhibitor Specialized Screening facility), Station Biologique de Roscoff, 29680 Roscoff, France
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, 2520 Potchefstroom, South Africa
| | | | - Olivier Sire
- IRDL UMR CNRS 6027, Université Bretagne Sud, 56017 Vannes, France
| | - Hedi Ben Mansour
- Research Unit of Analysis and Process Applied on the Environment─APAE UR17ES32, Higher Institute of Applied Sciences and Technology, Mahdia, University of Monastir, TN5121 Monastir, Tunisia
| | | |
Collapse
|
4
|
A review on cyclin-dependent kinase 5: An emerging drug target for neurodegenerative diseases. Int J Biol Macromol 2023; 230:123259. [PMID: 36641018 DOI: 10.1016/j.ijbiomac.2023.123259] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
Cyclin-dependent kinase 5 (CDK5) is the serine/threonine-directed kinase mainly found in the brain and plays a significant role in developing the central nervous system. Recent evidence suggests that CDK5 is activated by specific cyclins regulating its expression and activity. P35 and p39 activate CDK5, and their proteolytic degradation produces p25 and p29, which are stable products involved in the hyperphosphorylation of tau protein, a significant hallmark of various neurological diseases. Numerous high-affinity inhibitors of CDK5 have been designed, and some are marketed drugs. Roscovitine, like other drugs, is being used to minimize neurological symptoms. Here, we performed an extensive literature analysis to highlight the role of CDK5 in neurons, synaptic plasticity, DNA damage repair, cell cycle, etc. We have investigated the structural features of CDK5, and their binding mode with the designed inhibitors is discussed in detail to develop attractive strategies in the therapeutic targeting of CDK5 for neurodegenerative diseases. This review provides deeper mechanistic insights into the therapeutic potential of CDK5 inhibitors and their implications in the clinical management of neurodegenerative diseases.
Collapse
|
5
|
Abstract
The chronification of pain can be attributed to changes in membrane receptors and channels underlying neuronal plasticity and signal transduction largely within nociceptive neurons that initiate and maintain pathological pain states. These proteins are subject to dynamic modification by posttranslational modifications, creating a code that controls protein function in time and space. Phosphorylation is an important posttranslational modification that affects ∼30% of proteins in vivo. Increased phosphorylation of various nociceptive ion channels and of their modulators underlies sensitization of different pain states. Cyclin-dependent kinases are proline-directed serine/threonine kinases that impact various biological and cellular systems. Cyclin-dependent kinase 5 (Cdk5), one member of this kinase family, and its activators p35 and p39 are expressed in spinal nerves, dorsal root ganglia, and the dorsal horn of the spinal cord. In neuropathic pain conditions, expression and/or activity of Cdk5 is increased, implicating Cdk5 in nociception. Experimental evidence suggests that Cdk5 is regulated through its own phosphorylation, through increasing p35's interaction with Cdk5, and through cleavage of p35 into p25. This narrative review discusses the molecular mechanisms of Cdk5-mediated regulation of target proteins involved in neuropathic pain. We focus on Cdk5 substrates that have been linked to nociceptive pathways, including channels (eg, transient receptor potential cation channel and voltage-gated calcium channel), proteins involved in neurotransmitter release (eg, synaptophysin and collapsin response mediator protein 2), and receptors (eg, glutamate, purinergic, and opioid). By altering the phosphoregulatory "set point" of proteins involved in pain signaling, Cdk5 thus appears to be an attractive target for treating neuropathic pain conditions.
Collapse
|
6
|
Sharma S, Sicinski P. A kinase of many talents: non-neuronal functions of CDK5 in development and disease. Open Biol 2020; 10:190287. [PMID: 31910742 PMCID: PMC7014686 DOI: 10.1098/rsob.190287] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cyclin-dependent kinase 5 (CDK5) represents an unusual member of the family of cyclin-dependent kinases, which is activated upon binding to non-cyclin p35 and p39 proteins. The role of CDK5 in the nervous system has been very well established. In addition, there is growing evidence that CDK5 is also active in non-neuronal tissues, where it has been postulated to affect a variety of functions such as the immune response, angiogenesis, myogenesis, melanogenesis and regulation of insulin levels. Moreover, high levels of CDK5 have been observed in different tumour types, and CDK5 was proposed to play various roles in the tumorigenic process. In this review, we discuss these various CDK5 functions in normal physiology and disease, and highlight the therapeutic potential of targeting CDK5.
Collapse
Affiliation(s)
- Samanta Sharma
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Piotr Sicinski
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02215, USA
| |
Collapse
|
7
|
Cyclin-dependent kinase inhibition: an opportunity to target protein-protein interactions. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 121:115-141. [PMID: 32312419 DOI: 10.1016/bs.apcsb.2019.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Cyclin-dependent kinases (CDKs) play an integral part in cellular activities. To date, most of the activities have been evaluated in the cell cycle and transcription. Several diseases are affected by abnormalities in CDKs, related-pathways, or proteins that regulate CDK activity. CDKs are primarily dependent on activation by binding other proteins, namely Cyclins. In addition, phosphorylation of key CDK residues also plays a major part in CDK activity. To date, the most successful drugs have been developed against CDK4 and CDK6 and are FDA approved for use in advanced breast cancer. However, this is likely only a small fraction of the potential for targeting CDKs as a strategy against cancer and other diseases. Based on the extensive protein-protein interactions made by CDKs with other proteins (Cyclins and others), there are numerous possibilities for targeting strategies against protein-protein interactions. Here we describe the predominant roles of CDKs in the cell, key interacting proteins, significant 3-dimensional structural characteristics, and summarize the work-to-date in inhibition of CDKs.
Collapse
|
8
|
CDK5: Key Regulator of Apoptosis and Cell Survival. Biomedicines 2019; 7:biomedicines7040088. [PMID: 31698798 PMCID: PMC6966452 DOI: 10.3390/biomedicines7040088] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/14/2022] Open
Abstract
The atypical cyclin-dependent kinase 5 (CDK5) is considered as a neuron-specific kinase that plays important roles in many cellular functions including cell motility and survival. The activation of CDK5 is dependent on interaction with its activator p35, p39, or p25. These activators share a CDK5-binding domain and form a tertiary structure similar to that of cyclins. Upon activation, CDK5/p35 complexes localize primarily in the plasma membrane, cytosol, and perinuclear region. Although other CDKs are activated by cyclins, binding of cyclin D and E showed no effect on CDK5 activation. However, it has been shown that CDK5 can be activated by cyclin I, which results in anti-apoptotic functions due to the increased expression of Bcl-2 family proteins. Treatment with the CDK5 inhibitor roscovitine sensitizes cells to heat-induced apoptosis and its phosphorylation, which results in prevention of the apoptotic protein functions. Here, we highlight the regulatory mechanisms of CDK5 and its roles in cellular processes such as gene regulation, cell survival, and apoptosis.
Collapse
|
9
|
Cortés N, Guzmán-Martínez L, Andrade V, González A, Maccioni RB. CDK5: A Unique CDK and Its Multiple Roles in the Nervous System. J Alzheimers Dis 2019; 68:843-855. [DOI: 10.3233/jad-180792] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Nicole Cortés
- Laboratory of Neurosciences, Faculty of Sciences, University of Chile, Santiago, Chile
- International Center for Biomedicine (ICC), Santiago, Chile
| | - Leonardo Guzmán-Martínez
- Laboratory of Neurosciences, Faculty of Sciences, University of Chile, Santiago, Chile
- International Center for Biomedicine (ICC), Santiago, Chile
| | - Víctor Andrade
- Laboratory of Neurosciences, Faculty of Sciences, University of Chile, Santiago, Chile
- International Center for Biomedicine (ICC), Santiago, Chile
| | - Andrea González
- Laboratory of Neurosciences, Faculty of Sciences, University of Chile, Santiago, Chile
- International Center for Biomedicine (ICC), Santiago, Chile
| | - Ricardo B. Maccioni
- Laboratory of Neurosciences, Faculty of Sciences, University of Chile, Santiago, Chile
- International Center for Biomedicine (ICC), Santiago, Chile
- Department of Neurological Sciences, Faculty of Medicine, East Campus, University of Chile, Santiago, Chile
| |
Collapse
|
10
|
Shukla R, Singh TR. Virtual screening, pharmacokinetics, molecular dynamics and binding free energy analysis for small natural molecules against cyclin-dependent kinase 5 for Alzheimer's disease. J Biomol Struct Dyn 2019; 38:248-262. [PMID: 30688165 DOI: 10.1080/07391102.2019.1571947] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and characterized by brain cell death, memory loss and is the most common form of dementia. Although AD has devastating effects, however, drugs which can treat the AD remain limited. The cyclin-dependent kinase 5 (CDK5) has been recognized as being involved in the pathological hyperphosphorylation of tau protein, which leads to the formation of neurofibrillary tangles (NFTs). We utilized the structure-based virtual screening (SBVS) approach to find the potential inhibitors against HsCDK5. The natural compound subset from the ZINC database (n = 167,741) was retrieved and screened by using SBVS method. From here, we have predicted 297 potent inhibitors. These 297 compounds were evaluated through their pharmacokinetic properties by ADMET (absorption, distribution, metabolism, elimination/excretion and toxicity) descriptors. Finally, 17 compounds were selected and used for re-docking. After the refinement by molecular docking and by using drug-likeness analysis, we have identified four potential inhibitors (ZINC85877721, ZINC96114862, ZINC96115616 and ZINC96116231). All these four ligands were employed for 100 ns MDS study. From the root mean square deviation (RMSD), root mean square fluctuation (RMSF), Rg, number of hydrogen bonds, solvent accessible surface area (SASA), principal component analysis (PCA) and binding free energy analysis we have found that out of four inhibitors ZINC85877721 and ZINC96116231 showed good binding free energy of -198.84 and -159.32 kJ.mol-1, respectively, and also good in other structural analyses. Both compounds displayed excellent pharmacological and structural properties to be the drug candidates. Collectively, these findings recommend that two compounds have great potential to be a promising agent against AD to reduce the CDK5 induced hyperphosphorylation and could be considered as therapeutic agents for the AD.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Rohit Shukla
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology (JUIT), Waknaghat, India
| | - Tiratha Raj Singh
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology (JUIT), Waknaghat, India
| |
Collapse
|
11
|
Roach BL, Ngo JM, Limso C, Oloja KB, Bhandari D. Identification and characterization of a novel phosphoregulatory site on cyclin-dependent kinase 5. Biochem Biophys Res Commun 2018; 504:753-758. [PMID: 30217452 DOI: 10.1016/j.bbrc.2018.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
Cyclin-dependent kinase 5 (CDK5) is a serine/threonine kinase essential for embryonic development whose overactivation has been implicated in several pathologies including neurodegeneration, cancer cell metastasis and type II diabetes. Therefore, it is important to investigate molecular mechanism(s) that mediate regulation of CDK5 activity. Here we identify and characterize a novel phosphoregulatory site on CDK5. Our mass spectrometry analysis identified seven putative phosphorylation sites on CDK5. Using phosphomimetic and non-phosphorylatable mutants, we determined that phosphorylation of S47, one of the identified sites, renders the kinase catalytically inactive. The inactivation of the kinase due to the phosphomimetic change at S47 results from inhibition of its interaction with its cognate activator, p35. We connect the effect of this regulatory event to a cellular phenotype by showing that the S47D CDK5 mutant inhibits cell migration and promotes cell proliferation. Together, these results have uncovered a potential physiological mechanism to regulate CDK5 activity. The evolutionary placement of a phosphorylatable residue (S/T) at this position not only in CDK5 but also in the majority of other CDK family members suggests that this phosphosite may represent a shared regulatory mechanism across the CDK family.
Collapse
Affiliation(s)
- Brett Lee Roach
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, 90840, United States
| | - Jordan Matthew Ngo
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, 90840, United States
| | - Clariss Limso
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, 90840, United States
| | - Koyinsola Bolutife Oloja
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, 90840, United States
| | - Deepali Bhandari
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, 90840, United States.
| |
Collapse
|
12
|
Zhao G, Wang C, Wang H, Gao L, Liu Z, Xu B, Guo X. Characterization of the CDK5 gene in Apis cerana cerana (AccCDK5) and a preliminary identification of its activator gene, AccCDK5r1. Cell Stress Chaperones 2018; 23:13-28. [PMID: 28674940 PMCID: PMC5741578 DOI: 10.1007/s12192-017-0820-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 06/01/2017] [Accepted: 06/07/2017] [Indexed: 12/12/2022] Open
Abstract
Cyclin-dependent kinase 5 (CDK5) is an unusual CDK whose function has been implicated in protecting the central nervous system (CNS) from oxidative damage. However, there have been few studies of CDK5 in insects. In this study, we identified the AccCDK5 gene from Apis cerana cerana and investigated its role in oxidation resistance. We found that AccCDK5 is highly conserved across species and contains conserved features of the CDK5 family. The results of qPCR analysis indicated that AccCDK5 is highly expressed during the larval and pupal stages and in the adult head and muscle. We further observed that AccCDK5 is induced by several environmental oxidative stresses. Moreover, the overexpression of the AccCDK5 protein in E. coli enhances the resistance of the bacteria to oxidative stress. The activation of CDK5 requires binding to its activator. Therefore, we also identified and cloned cyclin-dependent kinase 5 regulatory subunit 1, which we named AccCDK5r1, from Apis cerana cerana. AccCDK5r1 contains a conserved cell localization targeting domain as well as binding and activation sites for CDK5. Yeast two-hybrid analysis demonstrated the interaction between AccCDK5 and AccCDK5r1. The expression patterns of the two genes were similar after stress treatment. Collectively, these results suggest that AccCDK5 plays a pivotal role in the response to oxidative stresses and that AccCDK5r1 is a potential activator of AccCDK5.
Collapse
Affiliation(s)
- Guangdong Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Chen Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Hongfang Wang
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Lijun Gao
- College of Life Sciences, Taishan Medical University, Taian, Shandong, 271016, People's Republic of China
| | - Zhenguo Liu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Baohua Xu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China.
| | - Xingqi Guo
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China.
| |
Collapse
|
13
|
Stetz G, Tse A, Verkhivker GM. Ensemble-based modeling and rigidity decomposition of allosteric interaction networks and communication pathways in cyclin-dependent kinases: Differentiating kinase clients of the Hsp90-Cdc37 chaperone. PLoS One 2017; 12:e0186089. [PMID: 29095844 PMCID: PMC5667858 DOI: 10.1371/journal.pone.0186089] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/25/2017] [Indexed: 12/24/2022] Open
Abstract
The overarching goal of delineating molecular principles underlying differentiation of protein kinase clients and chaperone-based modulation of kinase activity is fundamental to understanding activity of many oncogenic kinases that require chaperoning of Hsp70 and Hsp90 systems to attain a functionally competent active form. Despite structural similarities and common activation mechanisms shared by cyclin-dependent kinase (CDK) proteins, members of this family can exhibit vastly different chaperone preferences. The molecular determinants underlying chaperone dependencies of protein kinases are not fully understood as structurally similar kinases may often elicit distinct regulatory responses to the chaperone. The regulatory divergences observed for members of CDK family are of particular interest as functional diversification among these kinases may be related to variations in chaperone dependencies and can be exploited in drug discovery of personalized therapeutic agents. In this work, we report the results of a computational investigation of several members of CDK family (CDK5, CDK6, CDK9) that represented a broad repertoire of chaperone dependencies—from nonclient CDK5, to weak client CDK6, and strong client CDK9. By using molecular simulations of multiple crystal structures we characterized conformational ensembles and collective dynamics of CDK proteins. We found that the elevated dynamics of CDK9 can trigger imbalances in cooperative collective motions and reduce stability of the active fold, thus creating a cascade of favorable conditions for chaperone intervention. The ensemble-based modeling of residue interaction networks and community analysis determined how differences in modularity of allosteric networks and topography of communication pathways can be linked with the client status of CDK proteins. This analysis unveiled depleted modularity of the allosteric network in CDK9 that alters distribution of communication pathways and leads to impaired signaling in the client kinase. According to our results, these network features may uniquely define chaperone dependencies of CDK clients. The perturbation response scanning and rigidity decomposition approaches identified regulatory hotspots that mediate differences in stability and cooperativity of allosteric interaction networks in the CDK structures. By combining these synergistic approaches, our study revealed dynamic and network signatures that can differentiate kinase clients and rationalize subtle divergences in the activation mechanisms of CDK family members. The therapeutic implications of these results are illustrated by identifying structural hotspots of pathogenic mutations that preferentially target regions of the increased flexibility to enable modulation of activation changes. Our study offers a network-based perspective on dynamic kinase mechanisms and drug design by unravelling relationships between protein kinase dynamics, allosteric communications and chaperone dependencies.
Collapse
Affiliation(s)
- Gabrielle Stetz
- Department of Computational and Data Sciences, Schmid College of Science and Technology, Chapman University, Orange, California, United States of America
| | - Amanda Tse
- Department of Computational and Data Sciences, Schmid College of Science and Technology, Chapman University, Orange, California, United States of America
| | - Gennady M. Verkhivker
- Department of Computational and Data Sciences, Schmid College of Science and Technology, Chapman University, Orange, California, United States of America
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States of America
- * E-mail:
| |
Collapse
|
14
|
Dong K, Wang X, Yang X, Zhu X. Binding mechanism of CDK5 with roscovitine derivatives based on molecular dynamics simulations and MM/PBSA methods. J Mol Graph Model 2016; 68:57-67. [PMID: 27371933 DOI: 10.1016/j.jmgm.2016.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/21/2016] [Accepted: 06/15/2016] [Indexed: 12/11/2022]
Abstract
Roscovitine derivatives are potent inhibitors of cyclin-dependent kinase 5 (CDK5), but they exhibit different activities, which has not been understood clearly up to now. On the other hand, the task of drug design is difficult because of the fuzzy binding mechanism. In this context, the methods of molecular docking, molecular dynamics (MD) simulation, and binding free energy analysis are applied to investigate and reveal the detailed binding mechanism of four roscovitine derivatives with CDK5. The electrostatic and van der Waals interactions of the four inhibitors with CDK5 are analyzed and discussed. The calculated binding free energies in terms of MM-PBSA method are consistent with experimental ranking of inhibitor effectiveness for the four inhibitors. The hydrogen bonds of the inhibitors with Cys83 and Lys33 can stabilize the inhibitors in binding sites. The van der Waals interactions, especially the pivotal contacts with Ile10 and Leu133 have larger contributions to the binding free energy and play critical roles in distinguishing the variant bioactivity of four inhibitors. In terms of binding mechanism of the four inhibitors with CDK5 and energy contribution of fragments of each inhibitor, two new CDK5 inhibitors are designed and have stronger inhibitory potency.
Collapse
Affiliation(s)
- Keke Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
| | - Xuan Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
| | - Xueyu Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
| | - Xiaolei Zhu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China.
| |
Collapse
|
15
|
Czapski GA, Gąssowska M, Wilkaniec A, Chalimoniuk M, Strosznajder JB, Adamczyk A. The mechanisms regulating cyclin-dependent kinase 5 in hippocampus during systemic inflammatory response: The effect on inflammatory gene expression. Neurochem Int 2016; 93:103-12. [PMID: 26806339 DOI: 10.1016/j.neuint.2016.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
Cyclin-dependent kinase 5 (Cdk5) is critical for nervous system's development and function, and its aberrant activation contributes to pathomechanism of Alzheimer's disease and other neurodegenerative disorders. It was recently suggested that Cdk5 may participate in regulation of inflammatory signalling. The aim of this study was to analyse the mechanisms involved in regulating Cdk5 activity in the brain during systemic inflammatory response (SIR) as well as the involvement of Cdk5 in controlling the expression of inflammatory genes. Genetic and biochemical alterations in hippocampus were analysed 3 and 12 h after intraperitoneal injection of lipopolysaccharide. We observed an increase in both Cdk5 gene expression and protein level. Moreover, phosphorylation of Cdk5 on Ser159 was significantly enhanced. Also transcription of Cdk5-regulatory protein (p35/Cdk5r1) was augmented, and the level of p25, calpain-dependent cleavage product of p35, was increased. All these results demonstrated rapid activation of Cdk5 in the brain during SIR. Hyperactivity of Cdk5 contributed to enhanced phosphorylation of tau and glycogen synthase kinase 3β. Inhibition of Cdk5 with Roscovitine reduced activation of NF-κB and expression of inflammation-related genes, demonstrating the critical role of Cdk5 in regulation of gene transcription during SIR.
Collapse
Affiliation(s)
- Grzegorz A Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland.
| | - Magdalena Gąssowska
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Anna Wilkaniec
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Joanna B Strosznajder
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| |
Collapse
|
16
|
Grant NJ, Coates PJ, Woods YL, Bray SE, Morrice NA, Hastie CJ, Lamont DJ, Carey FA, Sutherland C. Phosphorylation of a splice variant of collapsin response mediator protein 2 in the nucleus of tumour cells links cyclin dependent kinase-5 to oncogenesis. BMC Cancer 2015; 15:885. [PMID: 26555036 PMCID: PMC4640224 DOI: 10.1186/s12885-015-1691-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 10/07/2015] [Indexed: 12/17/2022] Open
Abstract
Background Cyclin-dependent protein kinase-5 (CDK5) is an unusual member of the CDK family as it is not cell cycle regulated. However many of its substrates have roles in cell growth and oncogenesis, raising the possibility that CDK5 modulation could have therapeutic benefit. In order to establish whether changes in CDK5 activity are associated with oncogenesis one could quantify phosphorylation of CDK5 targets in disease tissue in comparison to appropriate controls. However the identity of physiological and pathophysiological CDK5 substrates remains the subject of debate, making the choice of CDK5 activity biomarkers difficult. Methods Here we use in vitro and in cell phosphorylation assays to identify novel features of CDK5 target sequence determinants that confer enhanced CDK5 selectivity, providing means to select substrate biomarkers of CDK5 activity with more confidence. We then characterize tools for the best CDK5 substrate we identified to monitor its phosphorylation in human tissue and use these to interrogate human tumour arrays. Results The close proximity of Arg/Lys amino acids and a proline two residues N-terminal to the phosphorylated residue both improve recognition of the substrate by CDK5. In contrast the presence of a proline two residues C-terminal to the target residue dramatically reduces phosphorylation rate. Serine-522 of Collapsin Response Mediator-2 (CRMP2) is a validated CDK5 substrate with many of these structural criteria. We generate and characterise phosphospecific antibodies to Ser522 and show that phosphorylation appears in human tumours (lung, breast, and lymphoma) in stark contrast to surrounding non-neoplastic tissue. In lung cancer the anti-phospho-Ser522 signal is positive in squamous cell carcinoma more frequently than adenocarcinoma. Finally we demonstrate that it is a specific and unusual splice variant of CRMP2 (CRMP2A) that is phosphorylated in tumour cells. Conclusions For the first time this data associates altered CDK5 substrate phosphorylation with oncogenesis in some but not all tumour types, implicating altered CDK5 activity in aspects of pathogenesis. These data identify a novel oncogenic mechanism where CDK5 activation induces CRMP2A phosphorylation in the nuclei of tumour cells. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1691-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Nicola J Grant
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Ninewells Medical School, DD1 9SY, Dundee, UK.
| | | | - Yvonne L Woods
- Department of Pathology, Ninewells Hospital, NHS Tayside, Dundee, UK.
| | - Susan E Bray
- Division of Cancer, University of Dundee, Dundee, UK.
| | | | - C James Hastie
- Division of Signal Transduction and Therapy, University of Dundee, Dundee, UK.
| | - Douglas J Lamont
- FingerPrints Proteomics Facility, University of Dundee, Dundee, UK.
| | - Francis A Carey
- Department of Pathology, Ninewells Hospital, NHS Tayside, Dundee, UK.
| | - Calum Sutherland
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Ninewells Medical School, DD1 9SY, Dundee, UK.
| |
Collapse
|
17
|
Takada S, Mizuno K, Saito T, Asada A, Giese KP, Hisanaga SI. Effects of p35 Mutations Associated with Mental Retardation on the Cellular Function of p35-CDK5. PLoS One 2015; 10:e0140821. [PMID: 26469698 PMCID: PMC4607440 DOI: 10.1371/journal.pone.0140821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/29/2015] [Indexed: 12/02/2022] Open
Abstract
p35 is an activation subunit of the cyclin-dependent kinase 5 (CDK5), which is a Ser/Thr kinase that is expressed predominantly in neurons. Disruption of the CDK5 or p35 (CDK5R1) genes induces abnormal neuronal layering in various regions of the mouse brain via impaired neuronal migration, which may be relevant for mental retardation in humans. Accordingly, mutations in the p35 gene were reported in patients with nonsyndromic mental retardation; however, their effect on the biochemical function of p35 has not been examined. Here, we studied the biochemical effect of mutant p35 on its known properties, i.e., stability, CDK5 activation, and cellular localization, using heterologous expression in cultured cells. We also examined the effect of the mutations on axon elongation in cultured primary neurons and migration of newborn neurons in embryonic brains. However, we did not detect any significant differences in the effects of the mutant forms of p35 compared with wild-type p35. Therefore, we conclude that these p35 mutations are unlikely to cause mental retardation.
Collapse
Affiliation(s)
- Shunsuke Takada
- Laboratory of Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo, Japan
| | - Keiko Mizuno
- Centre for Cellular Basis of Behavior, Institute of Psychiatry, King's College London, 125 Coldharbour Lane, London, United Kingdom
| | - Taro Saito
- Laboratory of Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo, Japan
| | - Akiko Asada
- Laboratory of Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo, Japan
| | - Karl Peter Giese
- Centre for Cellular Basis of Behavior, Institute of Psychiatry, King's College London, 125 Coldharbour Lane, London, United Kingdom
| | - Shin-ichi Hisanaga
- Laboratory of Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo, Japan
- * E-mail:
| |
Collapse
|
18
|
Abstract
Cyclin dependent kinase-5 (Cdk5), a family member of the cyclin-dependent kinases, plays a pivotal role in the central nervous system. During embryogenesis, Cdk5 is indispensable for brain development and, in the adult brain, it is essential for numerous neuronal processes, including higher cognitive functions such as learning and memory formation. However, Cdk5 activity becomes deregulated in several neurological disorders, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, which leads to neurotoxicity. Therefore, precise control over Cdk5 activity is essential for its physiological functions. This Commentary covers the various mechanisms of Cdk5 regulation, including several recently identified protein activators and inhibitors of Cdk5 that control its activity in normal and diseased brains. We also discuss the autoregulatory activity of Cdk5 and its regulation at the transcriptional, post-transcriptional and post-translational levels. We finally highlight physiological and pathological roles of Cdk5 in the brain. Specific modulation of these protein regulators is expected to provide alternative strategies for the development of effective therapeutic interventions that are triggered by deregulation of Cdk5.
Collapse
Affiliation(s)
- Kavita Shah
- Department of Chemistry, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Debomoy K Lahiri
- Laboratory of Molecular Neurogenetics, Departments of Psychiatry and of Medical & Molecular Genetics, Indiana University School of Medicine, Institute of Psychiatric Research, Neuroscience Research Building, 320 W. 15th St., Indianapolis, IN 46202, USA
| |
Collapse
|
19
|
Büchner A, Krumova P, Ganesan S, Bähr M, Eckermann K, Weishaupt JH. Sumoylation of p35 modulates p35/cyclin-dependent kinase (Cdk) 5 complex activity. Neuromolecular Med 2014; 17:12-23. [PMID: 25391294 DOI: 10.1007/s12017-014-8336-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 11/04/2014] [Indexed: 11/28/2022]
Abstract
Cyclin-dependent kinase (Cdk) 5 is critical for central nervous system development and neuron-specific functions including neurite outgrowth as well as synaptic function and plasticity. Cdk5 activity requires association with one of the two regulatory subunits, called p35 and p39. p35 redistribution as well as misregulation of Cdk5 activity is followed by cell death in several models of neurodegeneration. Posttranslational protein modification by small ubiquitin-related modifier (SUMO) proteins (sumoylation) has emerged as key regulator of protein targeting and protein/protein interaction. Under cell-free in vitro conditions, we found p35 covalently modified by SUMO1. Using both biochemical and FRET-/FLIM-based approaches, we demonstrated that SUMO2 is robustly conjugated to p35 in cells and identified the two major SUMO acceptor lysines in p35, K246 and K290. Furthermore, different degrees of oxidative stress resulted in differential p35 sumoylation, linking oxidative stress that is encountered in neurodegenerative diseases to the altered activity of Cdk5. Functionally, sumoylation of p35 increased the activity of the p35/Cdk5 complex. We thus identified a novel neuronal SUMO target and show that sumoylation is a likely candidate mechanism for the rapid modulation of p35/Cdk5 activity in physiological situations as well as in disease.
Collapse
Affiliation(s)
- Anja Büchner
- Department of Neurology, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | | | | | | | | | | |
Collapse
|
20
|
Zheng F, Quiocho FA. New structural insights into phosphorylation-free mechanism for full cyclin-dependent kinase (CDK)-cyclin activity and substrate recognition. J Biol Chem 2013; 288:30682-30692. [PMID: 24022486 DOI: 10.1074/jbc.m113.502773] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pho85 is a versatile cyclin-dependent kinase (CDK) found in budding yeast that regulates a myriad of eukaryotic cellular functions in concert with 10 cyclins (called Pcls). Unlike cell cycle CDKs that require phosphorylation of a serine/threonine residue by a CDK-activating kinase (CAK) for full activation, Pho85 requires no phosphorylation despite the presence of an equivalent residue. The Pho85-Pcl10 complex is a key regulator of glycogen metabolism by phosphorylating the substrate Gsy2, the predominant, nutritionally regulated form of glycogen synthase. Here we report the crystal structures of Pho85-Pcl10 and its complex with the ATP analog, ATPγS. The structure solidified the mechanism for bypassing CDK phosphorylation to achieve full catalytic activity. An aspartate residue, invariant in all Pcls, acts as a surrogate for the phosphoryl adduct of the phosphorylated, fully activated CDK2, the prototypic cell cycle CDK, complexed with cyclin A. Unlike the canonical recognition motif, SPX(K/R), of phosphorylation sites of substrates of several cell cycle CDKs, the motif in the Gys2 substrate of Pho85-Pcl10 is SPXX. CDK5, an important signal transducer in neural development and the closest known functional homolog of Pho85, does not require phosphorylation either, and we found that in its crystal structure complexed with p25 cyclin a water/hydroxide molecule remarkably plays a similar role to the phosphoryl or aspartate group. Comparison between Pho85-Pcl10, phosphorylated CDK2-cyclin A, and CDK5-p25 complexes reveals the convergent structural characteristics necessary for full kinase activity and the variations in the substrate recognition mechanism.
Collapse
Affiliation(s)
- Fei Zheng
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Florante A Quiocho
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.
| |
Collapse
|
21
|
Cyclin-dependent kinases: bridging their structure and function through computations. Future Med Chem 2011; 3:1551-9. [PMID: 21882947 DOI: 10.4155/fmc.11.113] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are one of the most promising target families for drug discovery for several diseases, such as cancer and neurodegenerative disorders. Over the years, structural insights on CDKs have demonstrated high protein plasticity, with several cases where two or more structures of the same protein adopt different conformations. This has generated a great deal of interest in understanding the relationship between CDK structure and function. Here, we highlight how computer simulations have recently contributed in characterizing some key rare and transient events in CDKs, such as the reaction transition state and activation loop movement. Although not yet fully defined, we can now portray the enzymatic mechanism and plasticity of CDKs at high spatial and temporal resolution. These theoretical studies bridge with experiments and highlight structural determinants that could help in designing specific CDK inhibitors.
Collapse
|
22
|
Xu J, Tsutsumi K, Tokuraku K, Estes KA, Hisanaga SI, Ikezu T. Actin interaction and regulation of cyclin-dependent kinase 5/p35 complex activity. J Neurochem 2011; 116:192-204. [PMID: 20492361 DOI: 10.1111/j.1471-4159.2010.06824.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyclin-dependent kinase 5 (Cdk5) plays a critical role during neurodevelopment, synaptic plasticity, and neurodegeneration. Cdk5 activity depends on association with neuronal proteins p35 and p25, a proteolytic product of p35. Cdk5 regulates the actin cytoskeletal dynamics that are essential for neuronal migration, neuritic growth, and synaptogenesis. However, little is known about the interaction of actin and Cdk5 and its effect on neuronal Cdk5 activity. In a previous study, we observed that Cdk5/p35 activity is negatively correlated with co-immunoprecipitated F-actin (filamentous actin) amounts in the mouse brain, and suggested that F-actin inhibits the formation of the Cdk5/p35 complex [Journal of Neuroscience (2008) vol. 28, p. 14511]. The experiments reported here were undertaken to elucidate the relationship between actin and the formation of the Cdk5/p35 complex and its activity. Instead of an F-actin-mediated inhibition, we propose that G-actin (globular actin) in the F-actin preparations is responsible for inhibiting Cdk5/p35 and Cdk5/p25 kinase activity. We found that F-actin binds to p35 but not p25 or Cdk5. We have shown that G-actin binds directly to Cdk5 without disrupting the formation of the Cdk5/p35 or Cdk5/p25 complexes. G-actin potently suppressed Cdk5/p35 and Cdk5/p25 activity when either histone H1 or purified human tau protein were used as substrates, indicating a substrate-independent inhibitory effect of G-actin on Cdk5 activity. Finally, G-actin suppressed the activity of Cdk5 immunoprecipitated from wild type and p35-deficient mouse brain, suggesting that G-actin suppresses endogenous Cdk5 activity in a p35-independent manner. Together, these results suggest a novel mechanism of actin cytoskeletal regulation of Cdk5/p35 activity.
Collapse
Affiliation(s)
- Jiqing Xu
- Center for Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | | | | | | | | | | |
Collapse
|
23
|
Hisanaga SI, Endo R. Regulation and role of cyclin-dependent kinase activity in neuronal survival and death. J Neurochem 2010; 115:1309-21. [PMID: 21044075 DOI: 10.1111/j.1471-4159.2010.07050.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cyclin-dependent kinase (Cdk)5 is a proline-directed Ser/Thr protein kinase that functions mainly in neurons and is activated by binding to a regulatory subunit, p35 or p39. Kinase activity is mainly determined by the amount of p35 available, which is controlled by a balance between synthesis and degradation. Kinase activity is also regulated by Cdk5 phosphorylation, but the activity of phosphorylated Cdk5 is in contrast to that of cycling Cdks. Cdk5 is a versatile protein kinase that regulates multiple neuronal activities including neuronal migration and synaptic signaling. Further, Cdk5 plays a role in both survival and death of neurons. Long-term inactivation of Cdk5 triggers cell death, and the survival activity of Cdk5 is apparent when neurons suffer from stress. In contrast, hyper-activation of Cdk5 by p25 promotes cell death, probably by reactivating cell-cycle machinery in the nucleus. The pro-death activity is suppressed by membrane association of Cdk5 via myristoylation of p35. Appropriate activity, localization, and regulation of Cdk5 may be critical for long-term survival of neurons, which is more than 80 years in the case of humans.
Collapse
Affiliation(s)
- Shin-ichi Hisanaga
- Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
| | | |
Collapse
|
24
|
Cardone A, Hassan SA, Albers RW, Sriram RD, Pant HC. Structural and dynamic determinants of ligand binding and regulation of cyclin-dependent kinase 5 by pathological activator p25 and inhibitory peptide CIP. J Mol Biol 2010; 401:478-92. [PMID: 20599546 DOI: 10.1016/j.jmb.2010.06.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/16/2010] [Accepted: 06/21/2010] [Indexed: 11/15/2022]
Abstract
The crystal structure of the cdk5/p25 complex has provided information on possible molecular mechanisms of the ligand binding, specificity, and regulation of the kinase. Comparative molecular dynamics simulations are reported here for physiological conditions. This study provides new insight on the mechanisms that modulate such processes, which may be exploited to control pathological activation by p25. The structural changes observed in the kinase are stabilized by a network of interactions involving highly conserved residues within the cyclin-dependent kinase (cdk) family. Collective motions of the proteins (cdk5, p25, and CIP) and their complexes are identified by principal component analysis, revealing two conformational states of the activation loop upon p25 complexation, which are absent in the uncomplexed kinase and not apparent from the crystal. Simulations of the uncomplexed inhibitor CIP show structural rearrangements and increased flexibility of the interfacial loop containing the critical residue E240, which becomes fully hydrated and available for interactions with one of several positively charged residues in the kinase. These changes provide a rationale for the observed high affinity and enhanced inhibitory action of CIP when compared to either p25 or the physiological activators of cdk5.
Collapse
Affiliation(s)
- A Cardone
- Information Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | | | | | | |
Collapse
|
25
|
Cell-Penetrating Fragments of the Cdk5 Regulatory Subunit Are Protective in Models of Neurodegeneration. Pharmaceuticals (Basel) 2010; 3:1232-1240. [PMID: 27713298 PMCID: PMC4034031 DOI: 10.3390/ph3041232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 04/16/2010] [Accepted: 04/21/2010] [Indexed: 11/29/2022] Open
Abstract
Cdk5 is essential for neuronal differentiation processes in the brain. Activation of Cdk5 requires the association with the mostly neuron-specific p35 or p39. Overactivation of CDK5 by cleavage of p35 into p25 is thought to be involved in neurodegenerative processes. Here, we have tested an approach to inhibit pathological Cdk5 activation with a Tat-linked dominant-negative fragment of p25. It reduced cell death induced by staurosporine and showed a tendency to alleviate manganese-induced cell death, while it did not protect against 6-OHDA toxicity. Our results suggest that the Tat technique is a suitable tool to inhibit dysregulated CDK5.
Collapse
|
26
|
Maddika S, Panigrahi S, Wiechec E, Wesselborg S, Fischer U, Schulze-Osthoff K, Los M. Unscheduled Akt-triggered activation of cyclin-dependent kinase 2 as a key effector mechanism of apoptin's anticancer toxicity. Mol Cell Biol 2009; 29:1235-48. [PMID: 19103742 PMCID: PMC2643822 DOI: 10.1128/mcb.00668-08] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/15/2008] [Accepted: 12/10/2008] [Indexed: 01/20/2023] Open
Abstract
Apoptin, a protein from the chicken anemia virus, has attracted attention because it specifically kills tumor cells while leaving normal cells unharmed. The reason for this tumor selectivity is unclear and depends on subcellular localization, as apoptin resides in the cytoplasm of normal cells but in the nuclei of transformed cells. It was shown that nuclear localization and tumor-specific killing crucially require apoptin's phosphorylation by an as yet unknown kinase. Here we elucidate the pathway of apoptin-induced apoptosis and show that it essentially depends on abnormal phosphatidylinositol 3-kinase (PI3-kinase)/Akt activation, resulting in the activation of the cyclin-dependent kinase CDK2. Inhibitors as well as dominant-negative mutants of PI3-kinase and Akt not only inhibited CDK2 activation but also protected cells from apoptin-induced cell death. Akt activated CDK2 by direct phosphorylation as well as by the phosphorylation-induced degradation of the inhibitor p27(Kip1). Importantly, we also identified CDK2 as the principal kinase that phosphorylates apoptin and is crucially required for apoptin-induced cell death. Immortalized CDK2-deficient fibroblasts and CDK2 knockdown cells were markedly protected against apoptin. Thus, our results not only decipher the pathway of apoptin-induced cell death but also provide mechanistic insights for the selective killing of tumor cells.
Collapse
Affiliation(s)
- Subbareddy Maddika
- Manitoba Institute of Cell Biology, CancerCare Manitoba, University of Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | | | | | | | | | | | | |
Collapse
|
27
|
Maddika S, Ande SR, Wiechec E, Hansen LL, Wesselborg S, Los M. Akt-mediated phosphorylation of CDK2 regulates its dual role in cell cycle progression and apoptosis. J Cell Sci 2008; 121:979-88. [PMID: 18354084 DOI: 10.1242/jcs.009530] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Here, we show that CDK2, an S-phase cyclin-dependent kinase, is a novel target for Akt during cell cycle progression and apoptosis. Akt phosphorylates CDK2 at threonine 39 residue both in vitro and in vivo. Although CDK2 threonine 39 phosphorylation mediated by Akt enhances cyclin-A binding, it is dispensable for its basal binding and the kinase activity. In addition, for the first time, we report a transient nucleo-cytoplasmic shuttling of Akt during specific stages of the cell cycle, in particular during the late S and G2 phases. The Akt that is re-localized to the nucleus phosphorylates CDK2 and causes the temporary cytoplasmic localization of the CDK2-cyclin-A complex. The CDK2 cytoplasmic redistribution is required for cell progression from S to G2-M phase, because the CDK2 T39A mutant, which lacks the phosphorylation site and is defective in cytoplasmic localization, severely affects cell cycle progression at the transition from S to G2-M. Interestingly, we also show that the Akt/CDK2 pathway is constitutively activated by some anticancer drugs, such as methotrexate and docetaxel, and under these conditions it promotes, rather than represses, cell death. Thus, the constitutive activation of the Akt/CDK2 pathway and changed subcellular localization promotes apoptosis. By contrast, the transient, physiological Akt/CDK2 activation is necessary for cell cycle progression.
Collapse
Affiliation(s)
- Subbareddy Maddika
- Manitoba Institute of Cell Biology, CancerCare Manitoba, University of Manitoba, Winnipeg, MB, R3E 0V9, Canada
| | | | | | | | | | | |
Collapse
|
28
|
Rosales JL, Sarker K, Ho N, Broniewska M, Wong P, Cheng M, van der Hoorn FA, Lee KY. ODF1 Phosphorylation by Cdk5/p35 Enhances ODF1-OIP1 Interaction. Cell Physiol Biochem 2008; 20:311-8. [PMID: 17762160 DOI: 10.1159/000107517] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2007] [Indexed: 11/19/2022] Open
Abstract
Cdk5 and p35 are integral components of the sperm tail outer dense fibers (ODFs), which contribute to the distinct morphology and function of the sperm tail. In this study, we sought to characterize and investigate the significance of Cdk5/p35 association with ODFs. We show that ODF2 interacts with Cdk5 and p35 but not with the Cdk5/p35 heterodimer. By using deletion mutants, the ODF2 binding region in p35 was mapped to residues 122 to 198. This overlaps the Cdk5 binding region in p35, explaining the inability of ODF2 to bind to the Cdk5/p35 complex. In vitro phosphorylation assay showed that although Cdk5/p35 does not phosphorylate ODF2, it phosphorylates ODF1. Mass spectrometry revealed that Cdk5/p35 specifically phosphorylates Ser193 in the ODF1 C-terminal region containing the Cys-X-Pro motif, the interaction site for the novel RING finger protein, ODF1 interacting protein (OIP1), a candidate E3 ubiquitin ligase, that also localizes in the sperm tail. Cdk5 phosphorylation of ODF1 Ser193 results in enhanced ODF1-OIP1 interaction. These findings suggest that Cdk5 may be important in promoting ODF1 degradation, and potentially, the detachment and fragmentation of the sperm tail following fertilization.
Collapse
Affiliation(s)
- Jesusa L Rosales
- Department of Cell Biology and Anatomy, Southern Alberta Cancer Research and Hotchkiss Brain Institutes, The University of Calgary, Calgary, Canada
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Clark CG, Alsmark UCM, Tazreiter M, Saito-Nakano Y, Ali V, Marion S, Weber C, Mukherjee C, Bruchhaus I, Tannich E, Leippe M, Sicheritz-Ponten T, Foster PG, Samuelson J, Noël CJ, Hirt RP, Embley TM, Gilchrist CA, Mann BJ, Singh U, Ackers JP, Bhattacharya S, Bhattacharya A, Lohia A, Guillén N, Duchêne M, Nozaki T, Hall N. Structure and content of the Entamoeba histolytica genome. ADVANCES IN PARASITOLOGY 2008; 65:51-190. [PMID: 18063096 DOI: 10.1016/s0065-308x(07)65002-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The intestinal parasite Entamoeba histolytica is one of the first protists for which a draft genome sequence has been published. Although the genome is still incomplete, it is unlikely that many genes are missing from the list of those already identified. In this chapter we summarise the features of the genome as they are currently understood and provide previously unpublished analyses of many of the genes.
Collapse
Affiliation(s)
- C G Clark
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Sato K, Zhu YS, Saito T, Yotsumoto K, Asada A, Hasegawa M, Hisanaga SI. Regulation of membrane association and kinase activity of Cdk5-p35 by phosphorylation of p35. J Neurosci Res 2008; 85:3071-8. [PMID: 17671990 DOI: 10.1002/jnr.21438] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although protein kinase Cdk5-p35 is important in many aspects of the development and function of the central nervous system, relatively little is known about its regulation. In the present study, we examined the relationship between the association of this kinase with membranes and its activity in perinatal and adult rat brains. Cdk5-p35 in perinatal brain exhibited higher activity than that found in adult tissue. Gel filtration chromatography revealed that a portion of Cdk5-p35 from fetal brain occurred as a soluble complex, whereas Cdk5-p35 in adult brain occurred predominantly as a membrane-bound complex. Furthermore, soluble Cdk5-p35 in perinatal brain displayed elevated kinase activity, whereas membrane-bound Cdk5-p35 was highly active only in the presence of detergent. This more active soluble form of Cdk5-p35 correlated to a form in which p35 was phosphorylated, whereas the less active membrane-bound form of Cdk5 correlated to the dephosphorylated form of p35, as evidenced by a downward shift in electrophoretic mobility. Cdk5 activity and transition from soluble to membrane-associated compartments could be modulated by conditions that affected the phosphorylation or dephosphorylation of p35. For example, dephosphorylation of p35 in brain extracts was suppressed by selective inhibition of protein phosphatase-1. Together, these results suggest that the kinase activity of Cdk5-p35 is regulated through its association with membranes, which in turn is under the control of Cdk5-dependent phosphorylation and protein phosphatase-1-dependent dephosphorylation of p35.
Collapse
Affiliation(s)
- Ko Sato
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
31
|
Structure of the Pho85-Pho80 CDK-cyclin complex of the phosphate-responsive signal transduction pathway. Mol Cell 2008; 28:614-23. [PMID: 18042456 DOI: 10.1016/j.molcel.2007.09.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 08/06/2007] [Accepted: 09/25/2007] [Indexed: 11/20/2022]
Abstract
The ability to sense and respond appropriately to environmental changes is a primary requirement of all living organisms. In response to phosphate limitation, Saccharomyces cerevisiae induces transcription of a set of genes involved in the regulation of phosphate acquisition from the ambient environment. A signal transduction pathway (the PHO pathway) mediates this response, with Pho85-Pho80 playing a vital role. Here we report the X-ray structure of Pho85-Pho80, a prototypic structure of a CDK-cyclin complex functioning in transcriptional regulation in response to environmental changes. The structure revealed a specific salt link between a Pho85 arginine and a Pho80 aspartate that makes phosphorylation of the Pho85 activation loop dispensable and that maintains a Pho80 loop conformation for possible substrate recognition. It further showed two sites on the Pho80 cyclin for high-affinity binding of the transcription factor substrate (Pho4) and the CDK inhibitor (Pho81) that are markedly distant to each other and the active site.
Collapse
|
32
|
A cell-based screening method for specifically detecting kinase activity. Anal Bioanal Chem 2007; 390:343-8. [PMID: 17985120 DOI: 10.1007/s00216-007-1685-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 10/08/2007] [Indexed: 10/22/2022]
Abstract
No universal approach has been reported for specific monitoring of the catalytic activity of a wide range of kinases in cells. The present study describes an original platform for detecting the autonomous activity of serine/threonine kinases in cells through the introduction of expression vectors encoding modified substrate kinase fusion proteins. The surrogate substrate used consists of the p53 tumor suppressor protein fused with individual kinase domains (Chk1, DYRK3, and Cdk5) at its carboxy-terminal through four tandem Gly-Gly-Gly-Gly-Ser repeats. After transfection into cells, phosphorylation of the p53 moiety could be specifically induced by the catalytic activity of kinases contained in the fusion protein. Moreover, p53 phosphorylation was significantly blocked when a kinase-inactive mutant was used as the fusion partner instead of the active kinase. Using this system, the cell-based evaluation of several Cdk5 inhibitors was demonstrated. Thus, this approach provides a novel platform for the specific, cell-based screening of inhibitors of a wide prospective range of protein kinases and is of tremendous potential for drug discovery efforts.
Collapse
|
33
|
Connell-Crowley L, Vo D, Luke L, Giniger E. Drosophila lacking the Cdk5 activator, p35, display defective axon guidance, age-dependent behavioral deficits and reduced lifespan. Mech Dev 2007; 124:341-9. [PMID: 17368005 PMCID: PMC2045698 DOI: 10.1016/j.mod.2007.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 02/07/2007] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
The cyclin-dependent kinase Cdk5 has attracted a great deal of attention both because of its roles in cell migration and axon patterning, and the extensive data implicating it in adult-onset neurodegeneration in mammals. Both the kinase activity and the biological effects of Cdk5 are absolutely dependent on association with an activating subunit, called p35. We show here that Drosophila lacking the Cdk5 activator, D-p35, display a wide range of defects in embryonic axon patterning. We further show that, while viable and fertile, p35 mutant adults display progressive, age-dependent loss of motor function and have a significantly shortened lifespan.
Collapse
Affiliation(s)
- Lisa Connell-Crowley
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program National Institute of Neurological Disorders and Stroke (NINDS), and, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bldg 37, Rm 1016, 37 Convent Drive Bethesda, MD 20892
| | - Duc Vo
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program National Institute of Neurological Disorders and Stroke (NINDS), and, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bldg 37, Rm 1016, 37 Convent Drive Bethesda, MD 20892
| | - Lori Luke
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program National Institute of Neurological Disorders and Stroke (NINDS), and, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bldg 37, Rm 1016, 37 Convent Drive Bethesda, MD 20892
| | - Edward Giniger
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program National Institute of Neurological Disorders and Stroke (NINDS), and, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bldg 37, Rm 1016, 37 Convent Drive Bethesda, MD 20892
| |
Collapse
|
34
|
Differential growth factor regulation of aspartyl-(asparaginyl)-beta-hydroxylase family genes in SH-Sy5y human neuroblastoma cells. BMC Cell Biol 2006; 7:41. [PMID: 17156427 PMCID: PMC1764734 DOI: 10.1186/1471-2121-7-41] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Accepted: 12/07/2006] [Indexed: 01/10/2023] Open
Abstract
Background Aspartyl (asparaginyl)-β-hydroxylase (AAH) hydroxylates Asp and Asn residues within EGF-like domains of Notch and Jagged, which mediate cell motility and differentiation. This study examines the expression, regulation and function of AAH, and its related transcripts, Humbug and Junctin, which lack catalytic domains, using SH-Sy5y neuroblastoma cells. Results Real time quantitative RT-PCR demonstrated 8- or 9-fold higher levels of Humbug than AAH and Junctin, and lower levels of all 3 transcripts in normal human brains compared with neuroblastic tumor cells. AAH and Humbug expression were significantly increased in response to insulin and IGF-I stimulation, and these effects were associated with increased directional motility. However, over-expression of AAH and not Humbug significantly increased motility. Treatment with chemical inhibitors of Akt, Erk MAPK, or cyclin-dependent kinase 5 (Cdk-5) significantly reduced IGF-I stimulated AAH and Humbug expression and motility relative to vehicle-treated control cells. In addition, significantly increased AAH and Humbug expression and directional motility were observed in cells co-transfected with Cdk-5 plus its p35 or p25 regulatory partner. Further studies demonstrated that activated Cdk-5 mediated its stimulatory effects on AAH through Erk MAPK and PI3 kinase. Conclusion AAH and Humbug are over-expressed in SH-Sy5y neuroblastoma cells, and their mRNAs are regulated by insulin/IGF-1 signaling through Erk MAPK, PI3 kinase-Akt, and Cdk-5, which are known mediators of cell migration. Although AAH and Humbug share regulatory signaling pathways, AAH and not Humbug mediates directional motility in SH-Sy5y neuroblastoma cells.
Collapse
|
35
|
Otyepka M, Bártová I, Kríz Z, Koca J. Different Mechanisms of CDK5 and CDK2 Activation as Revealed by CDK5/p25 and CDK2/Cyclin A Dynamics. J Biol Chem 2006; 281:7271-81. [PMID: 16407256 DOI: 10.1074/jbc.m509699200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A detailed analysis is presented of the dynamics of human CDK5 in complexes with the protein activator p25 and the purine-like inhibitor roscovitine. These and other findings related to the activation of CDK5 are critically reviewed from a molecular perspective. In addition, the results obtained on the behavior of CDK5 are compared with data on CDK2 to assess the differences and similarities between the two kinases in terms of (i) roscovitine binding, (ii) regulatory subunit association, (iii) conformational changes in the T-loop following CDK/regulatory subunit complex formation, and (iv) specificity in CDK/regulatory subunit recognition. An energy decomposition analysis, used for these purposes, revealed why the binding of p25 alone is sufficient to stabilize the extended active T-loop conformation of CDK5, whereas the equivalent conformational change in CDK2 requires both the binding of cyclin A and phosphorylation of the Thr(160) residue. The interaction energy of the CDK5 T-loop with p25 is about 26 kcal.mol(-1) greater than that of the CDK2 T-loop with cyclin A. The binding pattern between CDK5 and p25 was compared with that of CDK2/cyclin A to find specific regions involved in CDK/regulatory subunit recognition. The analyses performed revealed that the alphaNT-helix of cyclin A interacts with the alpha6-alpha7 loop and the alpha7 helix of CDK2, but these regions do not interact in the CDK5/p25 complex. Further differences between the CDK5/p25 and CDK2/cyclin A systems studied are discussed with respect to their specific functionality.
Collapse
Affiliation(s)
- Michal Otyepka
- Department of Physical Chemistry and Center for Biomolecules and Complex Molecular Systems, Palacký University, tr. Svobody 26, 771 46 Olomouc, Czech Republic.
| | | | | | | |
Collapse
|
36
|
Mishra L, Shetty K, Tang Y, Stuart A, Byers SW. The role of TGF-beta and Wnt signaling in gastrointestinal stem cells and cancer. Oncogene 2005; 24:5775-89. [PMID: 16123810 DOI: 10.1038/sj.onc.1208924] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The past three decades have seen an unremitting quest to identify and understand gastrointestinal stem cells, their plasticity in differentiating across cell types, as well as their role in normal, regenerative, and cancer cells. A fascinating hallmark of stem cells is their ability to undergo assymetric cell division, which entails replication of the DNA followed by division of the nucleus and partitioning of the cytoplasm to yield two different daughter cells: a stem cell as well as a committed progenitor cell, the latter proliferating into differentiated progeny. We are only just beginning to understand how normally quiescent, tissue-specific stem cells interpret a vast array of signals to develop into the gastrointestinal system. These signaling pathways include the transforming growth factor-beta (TGF-beta) superfamily, Wnt, FGFs, Hedgehog, Hox proteins that originate from surrounding mesodermal/stromal tissue as well as endodermal/epithelial tissue. TGF-beta and wnt proteins are key morphogens that ultimately influence cell division and cell fate, so that gut endodermal stem cells enter the cell cycle, and undergo cell division that ultimately leads to differentiated cells such as functional hepatocytes, gastric parietal cells, or gut epithelial cells. Disruptions and errors in this process usually lead to tissue-specific gastrointestinal cancers such as hepatocellular cancers, gastric adenocarcinomas, and colonic adenocarcinomas. An increasingly complex and coherent view of stem/progenitor cell signaling networks, which coordinate cell growth, proliferation, stress management, and survival, is helping to define the fragile areas where malignancies are likely to develop and shows promise for the development of better cancer therapies.
Collapse
Affiliation(s)
- Lopa Mishra
- Department of Surgery, Medicine, The Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA.
| | | | | | | | | |
Collapse
|
37
|
Lim ACB, Hou Z, Goh CP, Qi RZ. Protein kinase CK2 is an inhibitor of the neuronal Cdk5 kinase. J Biol Chem 2004; 279:46668-73. [PMID: 15342635 DOI: 10.1074/jbc.m404760200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The complex of Cdk5 and its neuronal activator p35 is a proline-directed Ser/Thr kinase that plays an important role in various neuronal functions. Deregulation of the Cdk5 enzymatic activity was found to associate with a number of neurodegenerative diseases. To search for regulatory factors of Cdk5-p35 in the brain, we developed biochemical affinity isolation using a recombinant protein comprising the N-terminal 149 amino acids of p35. The catalytic alpha-subunit of protein kinase CK2 (formerly known as casein kinase 2) was identified by mass spectrometry from the isolation. The association of CK2 with p35 and Cdk5 was demonstrated, and the CK2-binding sites were delineated in p35. Furthermore, CK2 displayed strong inhibition toward the Cdk5 activation by p35. The Cdk5 inhibition is dissociated from the kinase function of CK2 because the kinase-dead mutant of CK2 displayed the similar Cdk5 inhibitory activity as the wild-type enzyme. Further characterization showed that CK2 blocks the complex formation of Cdk5 and p35. Together, these findings suggest that CK2 acts as an inhibitor of Cdk5 in the brain.
Collapse
Affiliation(s)
- Anthony C B Lim
- Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609
| | | | | | | |
Collapse
|
38
|
|
39
|
Honma N, Asada A, Takeshita S, Enomoto M, Yamakawa E, Tsutsumi K, Saito T, Satoh T, Itoh H, Kaziro Y, Kishimoto T, Hisanaga SI. Apoptosis-associated tyrosine kinase is a Cdk5 activator p35 binding protein. Biochem Biophys Res Commun 2003; 310:398-404. [PMID: 14521924 DOI: 10.1016/j.bbrc.2003.08.143] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A 3(')-terminal fragment of a splice variant of KIAA0641, a human homologue of apoptosis-associated tyrosine kinase (AATYK), was screened from human brain cDNA libraries by a yeast two-hybrid system using a Cdk5 activator p35 as a bait. The cloned cDNA encoded 477 amino acids, composed of internal 458 amino acids of KIAA0641 and 19 amino acids unique to this variant after splicing, then referred to this clone as hAATYKs-p35BP (human AATYK short isoform-p35 binding polypeptide). Using GST-fusion protein, hAATYKs-p35BP was shown to bind to Cdk5/p35 in a rat brain extract. hAATYKs made by fusing the kinase domain of KIAA0641 to the N-terminus of hAATYKs-p35BP was used for binding to Cdk5/p35 in HEK293 cells. Both hAATYKs and KIAA0641 bound to and were phosphorylated by Cdk5/p35. These results suggest that both isoforms of hAATYK are novel Cdk5/p35-binding and substrate proteins.
Collapse
Affiliation(s)
- Naoyuki Honma
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Hachiohji, Tokyo 192-0397, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Developmental regulation of the proteolysis of the p35 cyclin-dependent kinase 5 activator by phosphorylation. J Neurosci 2003. [PMID: 12598607 DOI: 10.1523/jneurosci.23-04-01189.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cyclin-dependent kinase 5 (Cdk5), a cdc2-related kinase expressed in postmitotic neurons, is activated by association with a brain-specific activator, p35. It has been suggested that the conversion of p35 to p25 by the protease calpain is involved in neuronal cell death. However, p35 protein is turned over rapidly via proteasomal degradation in living neurons. In this study we show that the phosphorylation of p35 by Cdk5 suppresses the cleavage to p25 by calpain, whereas phosphorylation facilitates the proteasomal degradation of p35. The phosphorylation site in p35 that might be involved in preventing calpain cleavage was distinct from the phosphorylation site involved in facilitating proteasomal degradation. A phosphorylated form of p35 that was resistant to cleavage by calpain was more prevalent in the fetal brain, whereas the unphosphorylated form of p35 occurred in the adult brain. These results suggest that the phosphorylation of p35 serves as a protective mechanism that suppresses the generation of p25 in developing brains.
Collapse
|
41
|
Zheng YL, Li BS, Amin ND, Albers W, Pant HC. A peptide derived from cyclin-dependent kinase activator (p35) specifically inhibits Cdk5 activity and phosphorylation of tau protein in transfected cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4427-34. [PMID: 12230554 DOI: 10.1046/j.1432-1033.2002.03133.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cyclin-dependent kinase-5 (Cdk5) is a serine/threonine kinase activated by its neuron-specific activator, p35, or its truncated form, p25. It has been proposed that the deregulation of Cdk5 activity by association with p25 in human brain tissue disrupts the neuronal cytoskeleton and may be involved in neurodegenerative diseases such as Alzheimer's disease. In this study, we demonstrate that a short peptide (amino acid residues 154-279; Cdk5 inhibitory peptide; CIP), derived from p35, specifically inhibits Cdk5 activity in vitro and in HEK293 cells cotransfected with the peptide and Cdk5/p25, but had no effect on endogenous cdc2 kinase activity. Moreover, we demonstrate that the phosphorylation of tau in HEK293 cells, cotransfected with Cdk5/p25 and CIP, is effectively reduced. These results suggest that CIP specifically inhibits both Cdk5/p25 complex activity and the tau hyperphosphorylation induced by Cdk5/p25. The elucidation of the molecular basis of p25 activation and CIP inhibition of Cdk5 activity may provide insight into mechanisms underlying the pathology of Alzheimer's disease and contribute to therapeutic strategies.
Collapse
Affiliation(s)
- Ya-Li Zheng
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda 20892, USA
| | | | | | | | | |
Collapse
|
42
|
Zhang J, Luan CH, Chou KC, Johnson GVW. Identification of the N-terminal functional domains of Cdk5 by molecular truncation and computer modeling. Proteins 2002; 48:447-53. [PMID: 12112670 DOI: 10.1002/prot.10173] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cyclin dependent kinase (Cdk) 5, an atypical member of the Cdk family, plays a fundamental role in the development of the nervous system, and may also be involved in the pathogenesis of certain neurodegenerative diseases. Further, Cdk5 is activated by the specific regulatory proteins p39, p35, or p25 rather than cyclins, and in contrast to other members of the Cdk family is not involved in the progression of the cell cycle. A three-dimensional computer model of Cdk5-p25-ATP has been generated previously [Chou et al., Biochem Biophys Res Commun 1999;259:420-428], providing a structural basis for the study of the mechanisms of Cdk5 activation. To assess the predicted ATP and p25 binding domains at the N-terminal of Cdk5, two mutants of Cdk5 were prepared in which amino acids 9-15 (Delta9-15) or 9-47 (Delta9-47) were deleted. The results of these studies clearly demonstrate that an N-terminal loop and the PSSALRE helix are indispensable for Cdk5-p25 interactions, and amino acids 9-15 are necessary for ATP binding but are not involved in Cdk5-p25 interactions. Predicted models of Delta9-15 Cdk5 and Delta9-47 Cdk5 were generated, and were used to interpret the experimental data. The experimental and molecular modeling results confirm and extend specific aspects of the original predicted computer model, and may provide useful information for the design of highly selective inhibitors of Cdk5, which could be used in the treatment of certain neurodegenerative conditions.
Collapse
Affiliation(s)
- Jianwen Zhang
- Department of Psychiatry, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, USA
| | | | | | | |
Collapse
|
43
|
Patzke H, Tsai LH. Calpain-mediated cleavage of the cyclin-dependent kinase-5 activator p39 to p29. J Biol Chem 2002; 277:8054-60. [PMID: 11784720 DOI: 10.1074/jbc.m109645200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The activity of cyclin-dependent kinase-5 (Cdk5) is tightly regulated by binding of its neuronal activators p35 and p39. Upon neurotoxic insults, p35 is cleaved to p25 by the Ca(2+)-dependent protease calpain. p25 is accumulated in ischemic brains and in brains of patients with Alzheimer's disease. p25 deregulates Cdk5 activity by causing prolonged activation and mislocalization of Cdk5. It is unknown whether p39, which is expressed throughout the adult rat brain, is cleaved by calpain, and whether this contributes to deregulation of Cdk5. Here, we show that calpain cleaved p39 in vitro, resulting in generation of a C-terminal p29 fragment. In vivo, p29 was generated in ischemic brain concomitant with increased calpain activity. In fresh brain lysates, generation of p29 was Ca(2+)-dependent, and calpain inhibitors abolished p29 production. The Ca(2+) ionophore ionomycin and the excitotoxin glutamate induced production of p29 in cultures of cortical neurons in a calpain-dependent manner. Like p25, p29 was more stable than p39 and caused redistribution of Cdk5 in cortical neurons. Our data suggest that neurotoxic insults lead to calpain-mediated conversion of p39 to p29, which might contribute to deregulation of Cdk5.
Collapse
Affiliation(s)
- Holger Patzke
- Department of Pathology, Harvard Medical School and the Howard Hughes Medical Institute, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
44
|
Qu D, Li Q, Lim HY, Cheung NS, Li R, Wang JH, Qi RZ. The protein SET binds the neuronal Cdk5 activator p35nck5a and modulates Cdk5/p35nck5a activity. J Biol Chem 2002; 277:7324-32. [PMID: 11741927 DOI: 10.1074/jbc.m107270200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The neuronal Cdk5 kinase is composed of the catalytic subunit Cdk5 and the activator protein p35(nck5a) or its isoform, p39(nck5ai). To identify novel p35(nck5a)- and p39(nck5ai)-binding proteins, fragments of p35(nck5a) and p39(nck5ai) were utilized in affinity isolation of binding proteins from rat brain homogenates, and the isolated proteins were identified using mass spectrometry. With this approach, the nuclear protein SET was shown to interact with the N-terminal regions of p35(nck5a) and p39(nck5ai). Our detailed characterization showed that the SET protein formed a complex with Cdk5/p35(nck5a) through its binding to p35(nck5a). The p35(nck5a)-interacting region was mapped to a predicted alpha-helix in SET. When cotransfected into COS-7 cells, SET and p35(nck5a) displayed overlapping intracellular distribution in the nucleus. The nuclear co-localization was corroborated by immunostaining data of endogenous SET and Cdk5/p35(nck5a) from cultured cortical neurons. Finally, we demonstrated that the activity of Cdk5/p35(nck5a), but not that of Cdk5/p25(nck5a), was enhanced upon binding to the SET protein. The tail region of SET, which is rich in acidic residues, is required for the stimulatory effect on Cdk5/p35(nck5a).
Collapse
Affiliation(s)
- Dianbo Qu
- Proteomics Group, Institute of Molecular and Cell Biology, National University of Singapore, 30 Medical Drive, Singapore 117609
| | | | | | | | | | | | | |
Collapse
|
45
|
Clare PM, Poorman RA, Kelley LC, Watenpaugh KD, Bannow CA, Leach KL. The cyclin-dependent kinases cdk2 and cdk5 act by a random, anticooperative kinetic mechanism. J Biol Chem 2001; 276:48292-9. [PMID: 11604388 DOI: 10.1074/jbc.m102034200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
cdk2.cyclin E and cdk5.p25 are two members of the cyclin-dependent kinase family that are potential therapeutic targets for oncology and Alzheimer's disease, respectively. In this study we have investigated the mechanism for these enzymes. Kinases catalyze the transfer of phosphate from ATP to a protein acceptor, thus utilizing two substrates, ATP and the target protein. For a two-substrate reaction, possible kinetic mechanisms include: ping-pong, sequential random, or sequential ordered. To determine the kinetic mechanism of cdk2.GST-cyclin E and cdk5.GST-p25, kinase activity was measured in experiments in which concentrations of peptide and ATP substrates were varied in the presence of dead-end inhibitors. A peptide identical to the peptide substrate, but with a substitution of valine for the phosphoacceptor threonine, competed with substrate with a K(i) value of 0.6 mm. An aminopyrimidine, PNU 112455A, was identified in a screen for inhibitors of cdk2. Nonlinear least squares and Lineweaver-Burk analyses demonstrated that the inhibitor PNU 112455A was competitive with ATP with a K(i) value of 2 microm. In addition, a co-crystal of PNU 112455A with cdk2 showed that the inhibitor binds in the ATP binding pocket of the enzyme. Analysis of the inhibitor data demonstrated that both kinases use a sequential random mechanism, in which either ATP or peptide may bind first to the enzyme active site. For both kinases, the binding of the second substrate was shown to be anticooperative, in that the binding of the first substrate decreases the affinity of the second substrate. For cdk2.GST-cyclin E the kinetic parameters were determined to be K(m, ATP) = 3.6 +/- 1.0 microm, K(m, peptide) = 4.6 +/- 1.4 microm, and the anticooperativity factor, alpha = 130 +/- 44. For cdk5.GST-p25, the K(m, ATP) = 3.2 +/- 0.7 microm, K(m, peptide) = 1.6 +/- 0.3 microm, and alpha = 7.2 +/- 1.8.
Collapse
Affiliation(s)
- P M Clare
- Department of Cell and Molecular Biology, Pharmacia Corporation, Kalamazoo, Michigan 49007-4940, USA
| | | | | | | | | | | |
Collapse
|
46
|
Vincent I, Bu B, Hudson K, Husseman J, Nochlin D, Jin L. Constitutive Cdc25B tyrosine phosphatase activity in adult brain neurons with M phase-type alterations in Alzheimer's disease. Neuroscience 2001; 105:639-50. [PMID: 11516829 DOI: 10.1016/s0306-4522(01)00219-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Cdc2/cyclin B kinase is a critical regulator of mitosis that is normally absent from terminally differentiated neurons of adult brain. However, unscheduled expression and activation of Cdc2/cyclin B has been seen in neurons undergoing degeneration in Alzheimer's disease. The presence of this mitotic kinase correlates with accumulation of mitotic phosphoepitopes in protein components of the hallmark neurofibrillary tangles. Of importance to the pathogenic mechanism of Alzheimer's disease is the striking appearance of Cdc2/cyclin B and mitotic phosphoepitopes prior to neurofibrillary tangle formation, which has suggested that a misappropriate mitotic cascade initiates and mediates the neurodegenerative process. To explain the atypical activation of Cdc2/cyclin B in degenerating neurons we have investigated the enzyme responsible for Cdc2/cyclin B activation in mitotic cells, i.e. the Cdc25B tyrosine phosphatase, in Alzheimer's disease brain. Although the enzyme appeared abundant in affected neurons, it was also evident in unaffected neurons of Alzheimer's disease and control brain. Thus, we have found, surprisingly, that Cdc25B is a normal constituent of adult brain neurons, with detectable basal levels of activity. In Alzheimer's disease the levels and activity of the enzyme are elevated, and the active enzyme predominates in the cytoplasmic compartment of neurons. Consistent with these M phase-type changes, Cdc25B displays increased immunoreactivity towards the MPM-2 mitotic phosphoepitope antibody. We propose that aberrant expression of Cdc2/cyclin B in Alzheimer's disease leads to potentiation of mitotic activation mediated by constitutive neuronal Cdc25B activity. As a result, various downstream indices of mitotic events are generated, eventually culminating in neurodegeneration. Our data also suggest that Cdc25B is functional in normal post-mitotic neurons lacking the mitotic Cdc2/cyclin B, but it does not appear to influence the activity of Cdk5, a Cdc2-like kinase that is particularly enriched in brain.
Collapse
Affiliation(s)
- I Vincent
- Department of Pathology, University of Washington, K056 HSB, P.O. Box 357705, Seattle, WA 98195, USA.
| | | | | | | | | | | |
Collapse
|
47
|
Abstract
Since it was identified a decade ago, cyclin-dependent kinase 5 (CDK5) has emerged as a crucial regulator of neuronal migration in the developing central nervous system. CDK5 phosphorylates a diverse list of substrates, implicating it in the regulation of a range of cellular processes - from adhesion and motility, to synaptic plasticity and drug addiction. Recent evidence indicates that deregulation of this kinase is involved in the pathology of neurodegenerative diseases.
Collapse
Affiliation(s)
- R Dhavan
- Department of Pathology, Harvard Medical School, Howard Hughes Medical Institute, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
48
|
Karaiskou A, Perez LH, Ferby I, Ozon R, Jessus C, Nebreda AR. Differential regulation of Cdc2 and Cdk2 by RINGO and cyclins. J Biol Chem 2001; 276:36028-34. [PMID: 11461916 DOI: 10.1074/jbc.m104722200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinases (Cdks) are key regulators of the eukaryotic cell division cycle. Cdk1 (Cdc2) and Cdk2 should be bound to regulatory subunits named cyclins as well as phosphorylated on a conserved Thr located in the T-loop for full enzymatic activity. Cdc2- and Cdk2-cyclin complexes can be inactivated by phosphorylation on the catalytic cleft-located Thr-14 and Tyr-15 residues or by association with inhibitory subunits such as p21(Cip1). We have recently identified a novel Cdc2 regulator named RINGO that plays an important role in the meiotic cell cycle of Xenopus oocytes. RINGO can bind and activate Cdc2 but has no sequence homology to cyclins. Here we report that, in contrast with Cdc2- cyclin complexes, the phosphorylation of Thr-161 is not required for full activation of Cdc2 by RINGO. We also show that RINGO can directly stimulate the kinase activity of Cdk2 independently of Thr-160 phosphorylation. Moreover, RINGO-bound Cdc2 and Cdk2 are both less susceptible to inhibition by p21(Cip1), whereas the Thr-14/Tyr-15 kinase Myt1 can negatively regulate the activity of Cdc2-RINGO with reduced efficiency. Our results indicate that Cdk-RINGO complexes may be active under conditions in which cyclin-bound Cdks are inhibited and can therefore play different regulatory roles.
Collapse
Affiliation(s)
- A Karaiskou
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
49
|
Tarricone C, Dhavan R, Peng J, Areces LB, Tsai LH, Musacchio A. Structure and regulation of the CDK5-p25(nck5a) complex. Mol Cell 2001; 8:657-69. [PMID: 11583627 DOI: 10.1016/s1097-2765(01)00343-4] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
CDK5 plays an indispensable role in the central nervous system, and its deregulation is involved in neurodegeneration. We report the crystal structure of a complex between CDK5 and p25, a fragment of the p35 activator. Despite its partial structural similarity with the cyclins, p25 displays an unprecedented mechanism for the regulation of a cyclin-dependent kinase. p25 tethers the unphosphorylated T loop of CDK5 in the active conformation. Residue Ser159, equivalent to Thr160 on CDK2, contributes to the specificity of the CDK5-p35 interaction. Its substitution with threonine prevents p35 binding, while the presence of alanine affects neither binding nor kinase activity. Finally, we provide evidence that the CDK5-p25 complex employs a distinct mechanism from the phospho-CDK2-cyclin A complex to establish substrate specificity.
Collapse
Affiliation(s)
- C Tarricone
- Structural Biology Unit, Department of Experimental Oncology, European Institute of Oncology, Via Ripamonti 435, I-20141 Milan, Italy
| | | | | | | | | | | |
Collapse
|
50
|
Affiliation(s)
- J W Harper
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
| | | |
Collapse
|