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Yang H, Zhang X, Wang C, Zhang H, Yi J, Wang K, Hou Y, Ji P, Jin X, Li C, Zhang M, Huang S, Jia H, Hu K, Mou L, Wang R. Microcolin H, a novel autophagy inducer, exerts potent antitumour activity by targeting PITPα/β. Signal Transduct Target Ther 2023; 8:428. [PMID: 37963877 PMCID: PMC10645841 DOI: 10.1038/s41392-023-01667-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 09/16/2023] [Accepted: 09/30/2023] [Indexed: 11/16/2023] Open
Abstract
The identification of effective drug targets and the development of bioactive molecules are areas of high need in cancer therapy. The phosphatidylinositol transfer protein alpha/beta isoform (PITPα/β) has been reported to play an essential role in integrating phosphoinositide trafficking and lipid metabolism in diverse cellular processes but remains unexplored as a potential target for cancer treatment. Herein, data analysis of clinical cancer samples revealed that PITPα/β expression is closely correlated with the poor prognosis. Target identification by chemical proteomic methods revealed that microcolin H, a naturally occurring marine lipopeptide, directly binds PITPα/β and displays antiproliferative activity on different types of tumour cell lines. Furthermore, we identified that microcolin H treatment increased the conversion of LC3I to LC3II, accompanied by a reduction of the level of p62 in cancer cells, leading to autophagic cell death. Moreover, microcolin H showed preeminent antitumour efficacy in nude mouse subcutaneous tumour models with low toxicity. Our discoveries revealed that by targeting PITPα/β, microcolin H induced autophagic cell death in tumours with efficient anti-proliferating activity, which sheds light on PITPα/β as a promising therapeutic target for cancer treatment.
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Grants
- 21807053 National Natural Science Foundation of China (National Science Foundation of China)
- the Ministry of Education “Peptide Drugs” Innovation Team(No. IRT_15R27, China);the Fundamental Research Funds for the Central Universities (No. lzujbky-2019-15, China);the CAMS Innovation Fund for Medical Sciences (CIFMS, Nos. 2021-I2M-1-026, 2022-I2M-2-002, China)
- the Ministry of Education “Peptide Drugs” Innovation Team (No. IRT_15R27, China)
- the Ministry of Education “Peptide Drugs” Innovation Team (No. IRT_15R27, China), the CAMS Innovation Fund for Medical Sciences (CIFMS, Nos. 2019-I2M-5-074, 2021-I2M-1-026, 2021-I2M-3-001, 2022-I2M-2-002, China),
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Affiliation(s)
- Hange Yang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Xiaowei Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Cong Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Hailong Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China.
| | - Juan Yi
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Kun Wang
- Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, P. R. China
| | - Yanzhe Hou
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Peihong Ji
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Xiaojie Jin
- Gansu University Key Laboratory for Molecular Medicine & Chinese Medicine Prevention and Treatment of Major Diseases, College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, China
| | - Chenghao Li
- Gansu University Key Laboratory for Molecular Medicine & Chinese Medicine Prevention and Treatment of Major Diseases, College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, China
| | - Min Zhang
- Gansu University Key Laboratory for Molecular Medicine & Chinese Medicine Prevention and Treatment of Major Diseases, College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, China
| | - Shan Huang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
| | - Haoyuan Jia
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China
- School of Life Science, Lanzhou University, 730000, Lanzhou, P. R. China
| | - Kuan Hu
- Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, P. R. China
| | - Lingyun Mou
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China.
- School of Life Science, Lanzhou University, 730000, Lanzhou, P. R. China.
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou University, Lanzhou, Gansu, P. R. China.
- Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, P. R. China.
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2
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Mallick R, Bhowmik P, Duttaroy AK. Targeting fatty acid uptake and metabolism in cancer cells: A promising strategy for cancer treatment. Biomed Pharmacother 2023; 167:115591. [PMID: 37774669 DOI: 10.1016/j.biopha.2023.115591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023] Open
Abstract
Despite scientific development, cancer is still a fatal disease. The development of cancer is thought to be significantly influenced by fatty acids. Several mechanisms that control fatty acid absorption and metabolism are reported to be altered in cancer cells to support their survival. Cancer cells can use de novo synthesis or uptake of extracellular fatty acid if one method is restricted. This factor makes it more difficult to target one pathway while failing to treat the disease properly. Side effects may also arise if several inhibitors simultaneously target many targets. If a viable inhibitor could work on several routes, the number of negative effects might be reduced. Comparative investigations against cell viability have found several potent natural and manmade substances. In this review, we discuss the complex roles that fatty acids play in the development of tumors and the progression of cancer, newly discovered and potentially effective natural and synthetic compounds that block the uptake and metabolism of fatty acids, the adverse side effects that can occur when multiple inhibitors are used to treat cancer, and emerging therapeutic approaches.
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Affiliation(s)
- Rahul Mallick
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Finland
| | - Prasenjit Bhowmik
- Department of Chemistry, Uppsala Biomedical Centre, Uppsala University, Sweden
| | - Asim K Duttaroy
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway.
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Das K, Nozaki T. Non-Vesicular Lipid Transport Machinery in Leishmania donovani: Functional Implications in Host-Parasite Interaction. Int J Mol Sci 2023; 24:10637. [PMID: 37445815 DOI: 10.3390/ijms241310637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 05/21/2023] [Accepted: 05/22/2023] [Indexed: 07/15/2023] Open
Abstract
Eukaryotic cells have distinct membrane-enclosed organelles, each with a unique biochemical signature and specialized function. The unique identity of each organelle is greatly governed by the asymmetric distribution and regulated intracellular movement of two important biomolecules, lipids, and proteins. Non-vesicular lipid transport mediated by lipid-transfer proteins (LTPs) plays essential roles in intra-cellular lipid trafficking and cellular lipid homeostasis, while vesicular transport regulates protein trafficking. A comparative analysis of non-vesicular lipid transport machinery in protists could enhance our understanding of parasitism and basis of eukaryotic evolution. Leishmania donovani, the trypanosomatid parasite, greatly depends on receptor-ligand mediated signalling pathways for cellular differentiation, nutrient uptake, secretion of virulence factors, and pathogenesis. Lipids, despite being important signalling molecules, have intracellular transport mechanisms that are largely unexplored in L. donovani. We have identified a repertoire of sixteen (16) potential lipid transfer protein (LTP) homologs based on a domain-based search on TriTrypDB coupled with bioinformatics analyses, which signifies the presence of well-organized lipid transport machinery in this parasite. We emphasized here their evolutionary uniqueness and conservation and discussed their potential implications for parasite biology with regards to future therapeutic targets against visceral leishmaniasis.
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Affiliation(s)
- Koushik Das
- Department of Allied Health Sciences, School of Health Sciences and Technology, University of Petroleum and Energy Studies, Dehradun 248007, India
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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Hippo pathway regulation by phosphatidylinositol transfer protein and phosphoinositides. Nat Chem Biol 2022; 18:1076-1086. [PMID: 35788180 DOI: 10.1038/s41589-022-01061-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/12/2022] [Indexed: 12/30/2022]
Abstract
The Hippo pathway plays a key role in development, organ size control and tissue homeostasis, and its dysregulation contributes to cancer. The LATS tumor suppressor kinases phosphorylate and inhibit the YAP/TAZ transcriptional co-activators to suppress gene expression and cell growth. Through a screen of marine natural products, we identified microcolin B (MCB) as a Hippo activator that preferentially kills YAP-dependent cancer cells. Structure-activity optimization yielded more potent MCB analogs, which led to the identification of phosphatidylinositol transfer proteins α and β (PITPα/β) as the direct molecular targets. We established a critical role of PITPα/β in regulating LATS and YAP. Moreover, we showed that PITPα/β influence the Hippo pathway via plasma membrane phosphatidylinositol-4-phosphate. This study uncovers a previously unrecognized role of PITPα/β in Hippo pathway regulation and as potential cancer therapeutic targets.
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Zingg JM, Stamatiou C, Montalto G, Daunert S. Modulation of CD36-mediated lipid accumulation and senescence by vitamin E analogs in monocytes and macrophages. Biofactors 2022; 48:665-682. [PMID: 35084073 DOI: 10.1002/biof.1821] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 12/14/2021] [Indexed: 01/10/2023]
Abstract
The CD36/FAT scavenger receptor/fatty acids transporter regulates cellular lipid accumulation important for inflammation, atherosclerosis, lipotoxicity, and initiation of cellular senescence. Here we compared the regulatory effects of the vitamin E analogs alpha-tocopherol (αT), alpha-tocopheryl phosphate (αTP), and αTP/βCD (a nanocarrier complex between αTP and β-cyclodextrin [βCD]) and investigated their regulatory effects on lipid accumulation, phagocytosis, and senescence in THP-1 monocytes and macrophages. Both, αTP and αTP/βCD inhibited CD36 surface exposition stronger than αT leading to more pronounced CD36-mediated events such as inhibition of DiI-labeled oxLDL uptake, phagocytosis of fluorescent Staphylococcus aureus bioparticles, and cell proliferation. When compared to βCD, the complex of αTP/βCD extracted cholesterol from cellular membranes with higher efficiency and was associated with the delivery of αTP to the cells. Interestingly, both, αTP and more so αTP/βCD inhibited lysosomal senescence-associated beta-galactosidase (SA-β-gal) activity and increased lysosomal pH, suggesting CD36-mediated uptake into the endo-lysosomal phagocytic compartment. Accordingly, the observed pH increase was more pronounced with αTP/βCD in macrophages whereas no significant increase occurred with αT, alpha-tocopheryl acetate (αTA) or βCD. In contrast to αT and αTA, the αTP molecule is di-anionic at neutral pH, but upon moving into the acidic endo-lysosomal compartment becomes protonated and thus is acting as a base. Moreover, it is expected to be retained in lysosomes since it still carries one negative charge, similar to lysosomotropic drugs. Thus, treatment with αTP or αTP/βCD and/or inhibition of conversion of αTP to αT as it occurs in aged cells may counteract CD36-mediated overlapping inflammatory, senescent, and atherosclerotic events.
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Affiliation(s)
- Jean-Marc Zingg
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
| | - Christina Stamatiou
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
| | - Giulia Montalto
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Section of General Pathology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
- University of Miami Clinical and Translational Science Institute, University of Miami, Miami, Florida, USA
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6
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Cheng Y, Bai F, Ren X, Sun R, Guo X, Liu W, Wang B, Yang Y, Zhang X, Xu Y, Li C, Yang X, Gao L, Ma C, Li X, Liang X. Phosphoinositide-binding protein TIPE1 promotes alternative activation of macrophages and tumor progression via PIP3/Akt/TGF-β axis. Cancer Res 2022; 82:1603-1616. [PMID: 35135809 DOI: 10.1158/0008-5472.can-21-0003] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 09/06/2021] [Accepted: 02/04/2022] [Indexed: 11/16/2022]
Abstract
Macrophages perform key and distinct functions in maintaining tissue homeostasis by finely tuning their activation state. Within the tumor microenvironment, macrophages are reshaped to drive tumor progression. Here we report that tumor necrosis factor α-induced protein 8-like 1 (TIPE1) is highly expressed in macrophages, and that depletion of TIPE1 impedes alternative activation of macrophages. TIPE1 enhanced activation of the PI3K/Akt pathway in macrophages by directly binding with and regulating the metabolism of phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3). Accordingly, inhibition of the PI3K/Akt pathway significantly attenuated the effect of TIPE1 on macrophage alternative activation. Tumor-associated macrophages (TAM) in human liver cancer and melanoma tissues showed significantly upregulated TIPE1 expression that negatively correlated with patient survival. In vitro and in vivo, TIPE1 knockdown in macrophages retarded the growth and metastasis of liver cancer and melanoma. Furthermore, blockade or depletion of TGF-β signaling in macrophages abrogated the effects of TIPE1 on tumor cell growth and migration. Together, these results highlight that the phosphoinositide-related signaling pathway involves reprogramming tumor-associated macrophages to optimize the microenvironment for cancer progression.
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Affiliation(s)
- Yang Cheng
- Department of Immunology, School of Basic Medical Science
| | - Fuxiang Bai
- Department of Tissue Engineering and Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration and Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration
| | - Xiaolei Ren
- Department of Immunology, School of Basic Medical Science
| | - Renhui Sun
- Department of Immunology, School of Basic Medical Science
| | - Xiaowei Guo
- Dept of Immunology, Shandong University School of Basic Medical Science
| | - Wen Liu
- Dept of Immunology, Shandong University School of Basic Medical Science
| | - Bo Wang
- School of Basic Medical Science
| | - Yongheng Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Shandong University
| | - Xiaolu Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Shandong University
| | - Yong Xu
- Dept of Immunology, Shandong University School of Basic Medical Science
| | - Chunyang Li
- Department of Histology and Embryology, School of Basic Medical Science, Shandong University
| | | | - Lifen Gao
- Shandong University School of Medicine, Immunology
| | | | - Xueen Li
- Qilu Hospital of Shandong University
| | - Xiaohong Liang
- Department of Immunology, School of Basic Medical Science
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Shang P, Stepicheva N, Teel K, McCauley A, Fitting CS, Hose S, Grebe R, Yazdankhah M, Ghosh S, Liu H, Strizhakova A, Weiss J, Bhutto IA, Lutty GA, Jayagopal A, Qian J, Sahel JA, Samuel Zigler J, Handa JT, Sergeev Y, Rajala RVS, Watkins S, Sinha D. βA3/A1-crystallin regulates apical polarity and EGFR endocytosis in retinal pigmented epithelial cells. Commun Biol 2021; 4:850. [PMID: 34239035 PMCID: PMC8266859 DOI: 10.1038/s42003-021-02386-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
The retinal pigmented epithelium (RPE) is a monolayer of multifunctional cells located at the back of the eye. High membrane turnover and polarization, including formation of actin-based apical microvilli, are essential for RPE function and retinal health. Herein, we demonstrate an important role for βA3/A1-crystallin in RPE. βA3/A1-crystallin deficiency leads to clathrin-mediated epidermal growth factor receptor (EGFR) endocytosis abnormalities and actin network disruption at the apical side that result in RPE polarity disruption and degeneration. We found that βA3/A1-crystallin binds to phosphatidylinositol transfer protein (PITPβ) and that βA3/A1-crystallin deficiency diminishes phosphatidylinositol 4,5-biphosphate (PI(4,5)P2), thus probably decreasing ezrin phosphorylation, EGFR activation, internalization, and degradation. We propose that βA3/A1-crystallin acquired its RPE function before evolving as a structural element in the lens, and that in the RPE, it modulates the PI(4,5)P2 pool through PITPβ/PLC signaling axis, coordinates EGFR activation, regulates ezrin phosphorylation and ultimately the cell polarity.
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Affiliation(s)
- Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadezda Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kenneth Teel
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Austin McCauley
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | | | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rhonda Grebe
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Anastasia Strizhakova
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Imran A Bhutto
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gerard A Lutty
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Jiang Qian
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | - J Samuel Zigler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James T Handa
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Raju V S Rajala
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Simon Watkins
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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8
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Emerging Prospects for Combating Fungal Infections by Targeting Phosphatidylinositol Transfer Proteins. Int J Mol Sci 2021; 22:ijms22136754. [PMID: 34201733 PMCID: PMC8269425 DOI: 10.3390/ijms22136754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/27/2022] Open
Abstract
The emergence of fungal “superbugs” resistant to the limited cohort of anti-fungal agents available to clinicians is eroding our ability to effectively treat infections by these virulent pathogens. As the threat of fungal infection is escalating worldwide, this dwindling response capacity is fueling concerns of impending global health emergencies. These developments underscore the urgent need for new classes of anti-fungal drugs and, therefore, the identification of new targets. Phosphoinositide signaling does not immediately appear to offer attractive targets due to its evolutionary conservation across the Eukaryota. However, recent evidence argues otherwise. Herein, we discuss the evidence identifying Sec14-like phosphatidylinositol transfer proteins (PITPs) as unexplored portals through which phosphoinositide signaling in virulent fungi can be chemically disrupted with exquisite selectivity. Recent identification of lead compounds that target fungal Sec14 proteins, derived from several distinct chemical scaffolds, reveals exciting inroads into the rational design of next generation Sec14 inhibitors. Development of appropriately refined next generation Sec14-directed inhibitors promises to expand the chemical weaponry available for deployment in the shifting field of engagement between fungal pathogens and their human hosts.
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Holič R, Šťastný D, Griač P. Sec14 family of lipid transfer proteins in yeasts. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158990. [PMID: 34118432 DOI: 10.1016/j.bbalip.2021.158990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022]
Abstract
The hydrophobicity of lipids prevents their free movement across the cytoplasm. To achieve highly heterogeneous and precisely regulated lipid distribution in different cellular membranes, lipids are transported by lipid transfer proteins (LTPs) in addition to their transport by vesicles. Sec14 family is one of the most extensively studied groups of LTPs. Here we provide an overview of Sec14 family of LTPs in the most studied yeast Saccharomyces cerevisiae as well as in other selected non-Saccharomyces yeasts-Schizosaccharomyces pombe, Kluyveromyces lactis, Candida albicans, Candida glabrata, Cryptococcus neoformans, and Yarrowia lipolytica. Discussed are specificities of Sec14-domain LTPs in various yeasts, their mode of action, subcellular localization, and physiological function. In addition, quite few Sec14 family LTPs are target of antifungal drugs, serve as modifiers of drug resistance or influence virulence of pathologic yeasts. Thus, they represent an important object of study from the perspective of human health.
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Affiliation(s)
- Roman Holič
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dominik Šťastný
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Peter Griač
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia.
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10
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Lete MG, Tripathi A, Chandran V, Bankaitis VA, McDermott MI. Lipid transfer proteins and instructive regulation of lipid kinase activities: Implications for inositol lipid signaling and disease. Adv Biol Regul 2020; 78:100740. [PMID: 32992233 PMCID: PMC7986245 DOI: 10.1016/j.jbior.2020.100740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 05/17/2023]
Abstract
Cellular membranes are critical platforms for intracellular signaling that involve complex interfaces between lipids and proteins, and a web of interactions between a multitude of lipid metabolic pathways. Membrane lipids impart structural and functional information in this regulatory circuit that encompass biophysical parameters such as membrane thickness and fluidity, as well as chaperoning the interactions of protein binding partners. Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play key roles in intracellular membrane signaling, and these involvements are translated into an impressively diverse set of biological outcomes. The phosphatidylinositol transfer proteins (PITPs) are key regulators of phosphoinositide signaling. Found in a diverse array of organisms from plants, yeast and apicomplexan parasites to mammals, PITPs were initially proposed to be simple transporters of lipids between intracellular membranes. It now appears increasingly unlikely that the soluble versions of these proteins perform such functions within the cell. Rather, these serve to facilitate the activity of intrinsically biologically insufficient inositol lipid kinases and, in so doing, promote diversification of the biological outcomes of phosphoinositide signaling. The central engine for execution of such functions is the lipid exchange cycle that is a fundamental property of PITPs. How PITPs execute lipid exchange remains very poorly understood. Molecular dynamics simulation approaches are now providing the first atomistic insights into how PITPs, and potentially other lipid-exchange/transfer proteins, operate.
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Affiliation(s)
- Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Institute Biofisika (UPV/EHU, CSIC) and University of the Basque Country, Leioa, Spain
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vijay Chandran
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
| | - Mark I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA.
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11
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Sugiura T, Nakao H, Ikeda K, Khan D, Nile AH, Bankaitis VA, Nakano M. Biophysical parameters of the Sec14 phospholipid exchange cycle - Effect of lipid packing in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183450. [PMID: 32828847 DOI: 10.1016/j.bbamem.2020.183450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 11/28/2022]
Abstract
Sec14, a yeast phosphatidylinositol/phosphatidylcholine transfer protein, functions at the trans-Golgi membranes. It lacks domains involved in protein-protein or protein-lipid interactions and consists solely of the Sec14 domain; hence, the mechanism underlying Sec14 function at proper sites remains unclear. In this study, we focused on the lipid packing of membranes and evaluated its association with in vitro Sec14 lipid transfer activity. Phospholipid transfer assays using pyrene-labelled phosphatidylcholine suggested that increased membrane curvature as well as the incorporation of phosphatidylethanolamine accelerated the lipid transfer. The quantity of membrane-bound Sec14 significantly increased in these membranes, indicating that "packing defects" of the membranes promote the membrane binding and phospholipid transfer of Sec14. Increased levels of phospholipid unsaturation promoted Sec14-mediated PC transfer, but had little effect on the membrane binding of the protein. Our results demonstrate the possibility that the location and function of Sec14 are regulated by the lipid packing states produced by a translocase activity at the trans-Golgi network.
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Affiliation(s)
- Taichi Sugiura
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Hiroyuki Nakao
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Keisuke Ikeda
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Danish Khan
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Aaron H Nile
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114, USA
| | - Vytas A Bankaitis
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA; Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114, USA
| | - Minoru Nakano
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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12
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Khan D, Lee D, Gulten G, Aggarwal A, Wofford J, Krieger I, Tripathi A, Patrick JW, Eckert DM, Laganowsky A, Sacchettini J, Lindahl P, Bankaitis VA. A Sec14-like phosphatidylinositol transfer protein paralog defines a novel class of heme-binding proteins. eLife 2020; 9:57081. [PMID: 32780017 PMCID: PMC7462610 DOI: 10.7554/elife.57081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/10/2020] [Indexed: 01/02/2023] Open
Abstract
Yeast Sfh5 is an unusual member of the Sec14-like phosphatidylinositol transfer protein (PITP) family. Whereas PITPs are defined by their abilities to transfer phosphatidylinositol between membranes in vitro, and to stimulate phosphoinositide signaling in vivo, Sfh5 does not exhibit these activities. Rather, Sfh5 is a redox-active penta-coordinate high spin FeIII hemoprotein with an unusual heme-binding arrangement that involves a co-axial tyrosine/histidine coordination strategy and a complex electronic structure connecting the open shell iron d-orbitals with three aromatic ring systems. That Sfh5 is not a PITP is supported by demonstrations that heme is not a readily exchangeable ligand, and that phosphatidylinositol-exchange activity is resuscitated in heme binding-deficient Sfh5 mutants. The collective data identify Sfh5 as the prototype of a new class of fungal hemoproteins, and emphasize the versatility of the Sec14-fold as scaffold for translating the binding of chemically distinct ligands to the control of diverse sets of cellular activities.
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Affiliation(s)
- Danish Khan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Dongju Lee
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States
| | - Gulcin Gulten
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Anup Aggarwal
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Joshua Wofford
- Department of Chemistry, Texas A&M University, College Station, United States.,Department of Chemistry, Charleston Southern University, North Charleston, United States
| | - Inna Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States
| | - John W Patrick
- Department of Chemistry, Texas A&M University, College Station, United States
| | - Debra M Eckert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, United States
| | - James Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Paul Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States.,Department of Chemistry, Texas A&M University, College Station, United States
| | - Vytas A Bankaitis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States.,Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States.,Department of Chemistry, Texas A&M University, College Station, United States
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13
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Balla T, Kim YJ, Alvarez-Prats A, Pemberton J. Lipid Dynamics at Contact Sites Between the Endoplasmic Reticulum and Other Organelles. Annu Rev Cell Dev Biol 2020; 35:85-109. [PMID: 31590585 DOI: 10.1146/annurev-cellbio-100818-125251] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phospholipids are synthesized primarily within the endoplasmic reticulum and are subsequently distributed to various subcellular membranes to maintain the unique lipid composition of specific organelles. As a result, in most cases, the steady-state localization of membrane phospholipids does not match their site of synthesis. This raises the question of how diverse lipid species reach their final membrane destinations and what molecular processes provide the energy to maintain the lipid gradients that exist between various membrane compartments. Recent studies have highlighted the role of inositol phospholipids in the nonvesicular transport of lipids at membrane contact sites. This review attempts to summarize our current understanding of these complex lipid dynamics and highlights their implications for defining future research directions.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Alejandro Alvarez-Prats
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
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14
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Koundouros N, Poulogiannis G. Reprogramming of fatty acid metabolism in cancer. Br J Cancer 2020; 122:4-22. [PMID: 31819192 PMCID: PMC6964678 DOI: 10.1038/s41416-019-0650-z] [Citation(s) in RCA: 705] [Impact Index Per Article: 176.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/21/2019] [Accepted: 11/01/2019] [Indexed: 02/08/2023] Open
Abstract
A common feature of cancer cells is their ability to rewire their metabolism to sustain the production of ATP and macromolecules needed for cell growth, division and survival. In particular, the importance of altered fatty acid metabolism in cancer has received renewed interest as, aside their principal role as structural components of the membrane matrix, they are important secondary messengers, and can also serve as fuel sources for energy production. In this review, we will examine the mechanisms through which cancer cells rewire their fatty acid metabolism with a focus on four main areas of research. (1) The role of de novo synthesis and exogenous uptake in the cellular pool of fatty acids. (2) The mechanisms through which molecular heterogeneity and oncogenic signal transduction pathways, such as PI3K-AKT-mTOR signalling, regulate fatty acid metabolism. (3) The role of fatty acids as essential mediators of cancer progression and metastasis, through remodelling of the tumour microenvironment. (4) Therapeutic strategies and considerations for successfully targeting fatty acid metabolism in cancer. Further research focusing on the complex interplay between oncogenic signalling and dysregulated fatty acid metabolism holds great promise to uncover novel metabolic vulnerabilities and improve the efficacy of targeted therapies.
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Affiliation(s)
- Nikos Koundouros
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - George Poulogiannis
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK.
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK.
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15
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Tripathi A, Martinez E, Obaidullah AJ, Lete MG, Lönnfors M, Khan D, Soni KG, Mousley CJ, Kellogg GE, Bankaitis VA. Functional diversification of the chemical landscapes of yeast Sec14-like phosphatidylinositol transfer protein lipid-binding cavities. J Biol Chem 2019; 294:19081-19098. [PMID: 31690622 DOI: 10.1074/jbc.ra119.011153] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/31/2019] [Indexed: 01/22/2023] Open
Abstract
Phosphatidylinositol-transfer proteins (PITPs) are key regulators of lipid signaling in eukaryotic cells. These proteins both potentiate the activities of phosphatidylinositol (PtdIns) 4-OH kinases and help channel production of specific pools of phosphatidylinositol 4-phosphate (PtdIns(4)P) dedicated to specific biological outcomes. In this manner, PITPs represent a major contributor to the mechanisms by which the biological outcomes of phosphoinositide are diversified. The two-ligand priming model proposes that the engine by which Sec14-like PITPs potentiate PtdIns kinase activities is a heterotypic lipid-exchange cycle where PtdIns is a common exchange substrate among the Sec14-like PITP family, but the second exchange ligand varies with the PITP. A major prediction of this model is that second-exchangeable ligand identity will vary from PITP to PITP. To address the heterogeneity in the second exchange ligand for Sec14-like PITPs, we used structural, computational, and biochemical approaches to probe the diversities of the lipid-binding cavity microenvironments of the yeast Sec14-like PITPs. The collective data report that yeast Sec14-like PITP lipid-binding pockets indeed define diverse chemical microenvironments that translate into differential ligand-binding specificities across this protein family.
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Affiliation(s)
- Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas 77843-1114
| | - Elliott Martinez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Ahmad J Obaidullah
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23298-0540
| | - Marta G Lete
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas 77843-1114
| | - Max Lönnfors
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas 77843-1114
| | - Danish Khan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Krishnakant G Soni
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas 77843-1114
| | - Carl J Mousley
- School of Biomedical Sciences, Curtin Health Innovation Research Institute (CHIRI), Faculty of Health Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Glen E Kellogg
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23298-0540
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas 77843-1114 .,Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128.,Department of Chemistry, Texas A&M University, College Station, Texas 77843-2128
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16
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Abstract
Polyphosphoinositides (PPIn) are essential signaling phospholipids that make remarkable contributions to the identity of all cellular membranes and signaling cascades in mammalian cells. They exert regulatory control over membrane homeostasis via selective interactions with cellular proteins at the membrane–cytoplasm interface. This review article briefly summarizes our current understanding of the key roles that PPIn play in orchestrating and regulating crucial electrical and chemical signaling events in mammalian neurons and the significant neuro-pathophysiological conditions that arise following alterations in their metabolism.
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Affiliation(s)
- Eamonn James Dickson
- Department Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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17
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Sugiura T, Takahashi C, Chuma Y, Fukuda M, Yamada M, Yoshida U, Nakao H, Ikeda K, Khan D, Nile AH, Bankaitis VA, Nakano M. Biophysical Parameters of the Sec14 Phospholipid Exchange Cycle. Biophys J 2018; 116:92-103. [PMID: 30580923 DOI: 10.1016/j.bpj.2018.11.3131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/24/2018] [Accepted: 11/28/2018] [Indexed: 12/23/2022] Open
Abstract
Sec14, the major yeast phosphatidylcholine (PC)/phosphatidylinositol (PI) transfer protein (PITP), coordinates PC and PI metabolism to facilitate an appropriate and essential lipid signaling environment for membrane trafficking from trans-Golgi membranes. The Sec14 PI/PC exchange cycle is essential for its essential biological activity, but fundamental aspects of how this PITP executes its lipid transfer cycle remain unknown. To address some of these outstanding issues, we applied time-resolved small-angle neutron scattering for the determination of protein-mediated intervesicular movement of deuterated and hydrogenated phospholipids in vitro. Quantitative analysis by small-angle neutron scattering revealed that Sec14 PI- and PC-exchange activities were sensitive to both the lipid composition and curvature of membranes. Moreover, we report that these two parameters regulate lipid exchange activity via distinct mechanisms. Increased membrane curvature promoted both membrane binding and lipid exchange properties of Sec14, indicating that this PITP preferentially acts on the membrane site with a convexly curved face. This biophysical property likely constitutes part of a mechanism by which spatial specificity of Sec14 function is determined in cells. Finally, wild-type Sec14, but not a mixture of Sec14 proteins specifically deficient in either PC- or PI-binding activity, was able to effect a net transfer of PI or PC down opposing concentration gradients in vitro.
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Affiliation(s)
- Taichi Sugiura
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Chisato Takahashi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Yusuke Chuma
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Masakazu Fukuda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Makiko Yamada
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Ukyo Yoshida
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hiroyuki Nakao
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Keisuke Ikeda
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Danish Khan
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Aaron H Nile
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, Texas
| | - Vytas A Bankaitis
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, Texas; Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, Texas
| | - Minoru Nakano
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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18
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Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
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Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
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19
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Das K, Nozaki T. Non-vesicular Lipid Transport Machinery in Entamoeba histolytica. Front Cell Infect Microbiol 2018; 8:315. [PMID: 30283742 PMCID: PMC6156432 DOI: 10.3389/fcimb.2018.00315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/20/2018] [Indexed: 12/18/2022] Open
Abstract
Eukaryotic cells are organized into separate membrane-bound compartments that have specialized biochemical signature and function. Maintenance and regulation of distinct identity of each compartment is governed by the uneven distribution and intra-cellular movement of two essential biomolecules, lipids, and proteins. Non-vesicular lipid transport mediated by lipid transfer proteins plays a pivotal role in intra-cellular lipid trafficking and homeostasis whereas vesicular transport plays a central role in protein trafficking. Comparative study of lipid transport machinery in protist helps to better understand the pathogenesis and parasitism, and provides insight into eukaryotic evolution. Amebiasis, which is caused by Entamoeba histolytica, is one of the major enteric infections in humans, resulting in 40–100 thousand deaths annually. This protist has undergone remarkable alterations in the content and function of its sub-cellular compartments as well represented by its unique diversification of mitochondrion-related organelle, mitosome. We conducted domain-based search on AmoebaDB coupled with bioinformatics analyses and identified 22 potential lipid transfer protein homologs in E. histolytica, which are grouped into several sub-classes. Such in silico analyses have demonstrated the existence of well-organized lipid transport machinery in this parasite. We summarized and discussed the conservation and unique features of the whole repertoire of lipid transport proteins in E. histolytica.
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Affiliation(s)
- Koushik Das
- Graduate School of Medicine, The University of Tokyo, Bunkyō, Japan
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Bunkyō, Japan
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20
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Do inositol supplements enhance phosphatidylinositol supply and thus support endoplasmic reticulum function? Br J Nutr 2018; 120:301-316. [PMID: 29859544 DOI: 10.1017/s0007114518000946] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review attempts to explain why consuming extra myoinositol (Ins), an essential component of membrane phospholipids, is often beneficial for patients with conditions characterised by insulin resistance, non-alcoholic fatty liver disease and endoplasmic reticulum (ER) stress. For decades we assumed that most human diets provide an adequate Ins supply, but newer evidence suggests that increasing Ins intake ameliorates several disorders, including polycystic ovary syndrome, gestational diabetes, metabolic syndrome, poor sperm development and retinopathy of prematurity. Proposed explanations often suggest functional enhancement of minor facets of Ins Biology such as insulin signalling through putative inositol-containing 'mediators', but offer no explanation for this selectivity. It is more likely that eating extra Ins corrects a deficiency of an abundant Ins-containing cell constituent, probably phosphatidylinositol (PtdIns). Much of a cell's PtdIns is in ER membranes, and an increase in ER membrane synthesis, enhancing the ER's functional capacity, is often an important part of cell responses to ER stress. This review: (a) reinterprets historical information on Ins deficiency as describing a set of events involving a failure of cells adequately to adapt to ER stress; (b) proposes that in the conditions that respond to dietary Ins there is an overstretching of Ins reserves that limits the stressed ER's ability to make the 'extra' PtdIns needed for ER membrane expansion; and (c) suggests that eating Ins supplements increases the Ins supply to Ins-deficient and ER-stressed cells, allowing them to make more PtdIns and to expand the ER membrane system and sustain ER functions.
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21
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Koe CT, Tan YS, Lönnfors M, Hur SK, Low CSL, Zhang Y, Kanchanawong P, Bankaitis VA, Wang H. Vibrator and PI4KIIIα govern neuroblast polarity by anchoring non-muscle myosin II. eLife 2018; 7:33555. [PMID: 29482721 PMCID: PMC5828666 DOI: 10.7554/elife.33555] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/26/2018] [Indexed: 12/19/2022] Open
Abstract
A central feature of most stem cells is the ability to self-renew and undergo differentiation via asymmetric division. However, during asymmetric division the role of phosphatidylinositol (PI) lipids and their regulators is not well established. Here, we show that the sole type I PI transfer protein, Vibrator, controls asymmetric division of Drosophilaneural stem cells (NSCs) by physically anchoring myosin II regulatory light chain, Sqh, to the NSC cortex. Depletion of vib or disruption of its lipid binding and transfer activities disrupts NSC polarity. We propose that Vib stimulates PI4KIIIα to promote synthesis of a plasma membrane pool of phosphatidylinositol 4-phosphate [PI(4)P] that, in turn, binds and anchors myosin to the NSC cortex. Remarkably, Sqh also binds to PI(4)P in vitro and both Vib and Sqh mediate plasma membrane localization of PI(4)P in NSCs. Thus, reciprocal regulation between Myosin and PI(4)P likely governs asymmetric division of NSCs. Stem cells are cells that can both make copies of themselves and make new cells of various types. They can either divide symmetrically to produce two identical new cells, or they can divide asymmetrically to produce two different cells. Asymmetric division happens because the two new cells contain different molecules. Stem cells drive asymmetric division by moving key molecules to one end of the cell before they divide. Asymmetric division is key to how neural stem cells produce new brain cells. Many studies have used the developing brain of the fruit fly Drosophila melanogaster to understand this process. Errors in asymmetric division can lead to too many stem cells or not enough brain cells. This can contribute to brain tumors and other neurological disorders. Fat molecules called phosphatidylinositol lipids are some of chemicals that cause asymmetry in neural stem cells. Yet, it is not clear how these lipid molecules affect cell behavior to turn stem cells into brain cells. The production of phosphatidylinositol lipids involves proteins called Vibrator and PI4KIIIα. Koe et al. examined the role of these two proteins in asymmetric cell division of neural stem cells in fruit flies. The results show that Vibrator activates PI4KIIIα, which leads to high levels of a phosphatidylinositol lipid called PI(4)P within the cell. These lipids act as an anchor for a group of proteins called myosin, part of the machinery that physically divides the cell. Hence, myosin and phosphatidylinositol lipids together control asymmetric division of neural stem cells. Further experiments used mouse proteins to compensate for defects in the equivalent fly proteins. The results suggest that the same mechanisms are likely to hold true in mammalian brains, although this still needs to be proven. Nevertheless, given that human equivalents of Vibrator and PI4KIIIα are associated with neurodegenerative disorders, schizophrenia or cancers, these new findings are likely to help scientists better to understand several human diseases.
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Affiliation(s)
- Chwee Tat Koe
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Ye Sing Tan
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Max Lönnfors
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | - Seong Kwon Hur
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | | | - Yingjie Zhang
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Pakorn Kanchanawong
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore.,Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | - Hongyan Wang
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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22
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Gong B, Shen W, Xiao W, Meng Y, Meng A, Jia S. The Sec14-like phosphatidylinositol transfer proteins Sec14l3/SEC14L2 act as GTPase proteins to mediate Wnt/Ca 2+ signaling. eLife 2017; 6. [PMID: 28463110 PMCID: PMC5423769 DOI: 10.7554/elife.26362] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/30/2017] [Indexed: 12/24/2022] Open
Abstract
The non-canonical Wnt/Ca2+ signaling pathway plays important roles in embryonic development, tissue formation and diseases. However, it is unclear how the Wnt ligand-stimulated, G protein-coupled receptor Frizzled activates phospholipases for calcium release. Here, we report that the zebrafish/human phosphatidylinositol transfer protein Sec14l3/SEC14L2 act as GTPase proteins to transduce Wnt signals from Frizzled to phospholipase C (PLC). Depletion of sec14l3 attenuates Wnt/Ca2+ responsive activity and causes convergent and extension (CE) defects in zebrafish embryos. Biochemical analyses in mammalian cells indicate that Sec14l3-GDP forms complex with Frizzled and Dishevelled; Wnt ligand binding of Frizzled induces translocation of Sec14l3 to the plasma membrane; and then Sec14l3-GTP binds to and activates phospholipase Cδ4a (Plcδ4a); subsequently, Plcδ4a initiates phosphatidylinositol-4,5-bisphosphate (PIP2) signaling, ultimately stimulating calcium release. Furthermore, Plcδ4a can act as a GTPase-activating protein to accelerate the hydrolysis of Sec14l3-bound GTP to GDP. Our data provide a new insight into GTPase protein-coupled Wnt/Ca2+ signaling transduction.
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Affiliation(s)
- Bo Gong
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Weimin Shen
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wanghua Xiao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yaping Meng
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Anming Meng
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shunji Jia
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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23
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Lipid transfer proteins and the tuning of compartmental identity in the Golgi apparatus. Chem Phys Lipids 2016; 200:42-61. [DOI: 10.1016/j.chemphyslip.2016.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
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24
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Kiełbowicz-Matuk A, Banachowicz E, Turska-Tarska A, Rey P, Rorat T. Expression and characterization of a barley phosphatidylinositol transfer protein structurally homologous to the yeast Sec14p protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 246:98-111. [PMID: 26993240 DOI: 10.1016/j.plantsci.2016.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/16/2016] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
Phosphatidylinositol transfer proteins (PITPs) include a large group of proteins implicated in the non-vesicular traffic of phosphatidylinositol (PI) between membranes. In yeast, the structure and function of the PITP Sec14-p protein have been well characterized. In contrast, the knowledge on plant PITP proteins is very scarce. In this work, we characterized a novel type of PITP protein in barley named HvSec14p and related to the yeast Sec14-p protein. Our data reveal that HvSec14p consists of only the Sec14p-domain structurally homologous to the yeast phosphoinositide binding domain. We show that HvSec14p expression is up-regulated at both transcript and protein levels at specific stages of development during seed formation and germination, and in leaves of a drought-tolerant barley genotype under osmotic constraints. Modeling analyses of the protein three-dimensional structure revealed its capacity to dock the phosphoinositides, PtdIns(3)P, PtdIns(4)P, PtdIns(5)P and PtdIns(3,5)P2. Consistently, the recombinant HvSec14p protein is able to bind in vitro most PIP types, the highest affinity being observed with PtdIns(3,5)P2. Based on the high gene expression at specific developmental stages and in drought-tolerant barley genotypes, we propose that HvSec14p plays essential roles in the biogenesis of membranes in expanding cells and in their preservation under osmotic stress conditions.
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Affiliation(s)
| | - Ewa Banachowicz
- Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
| | - Anna Turska-Tarska
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland.
| | - Pascal Rey
- CEA, DSV, IBEB, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance, F-13108, France; CNRS, UMR 7265 Biologie Végétale & Microbiologie Environnementale, Saint-Paul-lez-Durance, F-13108, France; Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
| | - Tadeusz Rorat
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland.
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25
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Huang J, Ghosh R, Bankaitis VA. Sec14-like phosphatidylinositol transfer proteins and the biological landscape of phosphoinositide signaling in plants. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1352-1364. [PMID: 27038688 DOI: 10.1016/j.bbalip.2016.03.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 01/01/2023]
Abstract
Phosphoinositides and soluble inositol phosphates are essential components of a complex intracellular chemical code that regulates major aspects of lipid signaling in eukaryotes. These involvements span a broad array of biological outcomes and activities, and cells are faced with the problem of how to compartmentalize and organize these various signaling events into a coherent scheme. It is in the arena of how phosphoinositide signaling circuits are integrated and, and how phosphoinositide pools are functionally defined and channeled to privileged effectors, that phosphatidylinositol (PtdIns) transfer proteins (PITPs) are emerging as critical players. As plant systems offer some unique advantages and opportunities for study of these proteins, we discuss herein our perspectives regarding the progress made in plant systems regarding PITP function. We also suggest interesting prospects that plant systems hold for interrogating how PITPs work, particularly in multi-domain contexts, to diversify the biological outcomes for phosphoinositide signaling. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Jin Huang
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA.
| | - Ratna Ghosh
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA
| | - Vytas A Bankaitis
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-1114 USA; Department of Chemistry, Texas A&M University, College Station, TX 77843-1114 USA.
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26
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Khan D, McGrath KR, Dorosheva O, Bankaitis VA, Tripathi A. Structural elements that govern Sec14-like PITP sensitivities to potent small molecule inhibitors. J Lipid Res 2016; 57:650-62. [PMID: 26921357 DOI: 10.1194/jlr.m066381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 12/15/2022] Open
Abstract
Sec14-like phosphatidylinositol transfer proteins (PITPs) play important biological functions in integrating multiple aspects of intracellular lipid metabolism with phosphatidylinositol-4-phosphate signaling. As such, these proteins offer new opportunities for highly selective chemical interference with specific phosphoinositide pathways in cells. The first and best characterized small molecule inhibitors of the yeast PITP, Sec14, are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs), and a hallmark feature of NPPMs is their exquisite targeting specificities for Sec14 relative to other closely related Sec14-like PITPs. Our present understanding of Sec14::NPPM binding interactions is based on computational docking and rational loss-of-function approaches. While those approaches have been informative, we still lack an adequate understanding of the basis for the high selectivity of NPPMs among closely related Sec14-like PITPs. Herein, we describe a Sec14 motif, which we term the VV signature, that contributes significantly to the NPPM sensitivity/resistance of Sec14-like phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer proteins. The data not only reveal previously unappreciated determinants that govern Sec14-like PITP sensitivities to NPPMs, but enable predictions of which Sec14-like PtdIns/PtdCho transfer proteins are likely to be NPPM resistant or sensitive based on primary sequence considerations. Finally, the data provide independent evidence in support of previous studies highlighting the importance of Sec14 residue Ser173 in the mechanism by which NPPMs engage and inhibit Sec14-like PITPs.
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Affiliation(s)
- Danish Khan
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Kaitlyn R McGrath
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Oleksandra Dorosheva
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Vytas A Bankaitis
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 Chemistry, Texas A&M University, College Station, TX 77843-2128
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
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27
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Musille PM, Kossmann BR, Kohn JA, Ivanov I, Ortlund EA. Unexpected Allosteric Network Contributes to LRH-1 Co-regulator Selectivity. J Biol Chem 2015; 291:1411-26. [PMID: 26553876 DOI: 10.1074/jbc.m115.662874] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Indexed: 11/06/2022] Open
Abstract
Phospholipids (PLs) are unusual signaling hormones sensed by the nuclear receptor liver receptor homolog-1 (LRH-1), which has evolved a novel allosteric pathway to support appropriate interaction with co-regulators depending on ligand status. LRH-1 plays an important role in controlling lipid and cholesterol homeostasis and is a potential target for the treatment of metabolic and neoplastic diseases. Although the prospect of modulating LRH-1 via small molecules is exciting, the molecular mechanism linking PL structure to transcriptional co-regulator preference is unknown. Previous studies showed that binding to an activating PL ligand, such as dilauroylphosphatidylcholine, favors LRH-1's interaction with transcriptional co-activators to up-regulate gene expression. Both crystallographic and solution-based structural studies showed that dilauroylphosphatidylcholine binding drives unanticipated structural fluctuations outside of the canonical activation surface in an alternate activation function (AF) region, encompassing the β-sheet-H6 region of the protein. However, the mechanism by which dynamics in the alternate AF influences co-regulator selectivity remains elusive. Here, we pair x-ray crystallography with molecular modeling to identify an unexpected allosteric network that traverses the protein ligand binding pocket and links these two elements to dictate selectivity. We show that communication between the alternate AF region and classical AF2 is correlated with the strength of the co-regulator interaction. This work offers the first glimpse into the conformational dynamics that drive this unusual PL-mediated nuclear hormone receptor activation.
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Affiliation(s)
- Paul M Musille
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | - Bradley R Kossmann
- the Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302
| | - Jeffrey A Kohn
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | - Ivaylo Ivanov
- the Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302
| | - Eric A Ortlund
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322 and
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28
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Sec14-like phosphatidylinositol-transfer proteins and diversification of phosphoinositide signalling outcomes. Biochem Soc Trans 2015; 42:1383-8. [PMID: 25233419 DOI: 10.1042/bst20140187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The physiological functions of phosphatidylinositol (PtdIns)-transfer proteins (PITPs)/phosphatidylcholine (PtdCho)-transfer proteins are poorly characterized, even though these proteins are conserved throughout the eukaryotic kingdom. Much of the progress in elucidating PITP functions has come from exploitation of genetically tractable model organisms, but the mechanisms for how PITPs execute their biological activities remain unclear. Structural and molecular dynamics approaches are filling in the details for how these proteins actually work as molecules. In the present paper, we discuss our recent work with Sec14-like PITPs and describe how PITPs integrate diverse territories of the lipid metabolome with phosphoinositide signalling.
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29
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Grabon A, Khan D, Bankaitis VA. Phosphatidylinositol transfer proteins and instructive regulation of lipid kinase biology. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:724-35. [PMID: 25592381 PMCID: PMC5221696 DOI: 10.1016/j.bbalip.2014.12.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/21/2014] [Accepted: 12/16/2014] [Indexed: 11/25/2022]
Abstract
Phosphatidylinositol is a metabolic precursor of phosphoinositides and soluble inositol phosphates. Both sets of molecules represent versatile intracellular chemical signals in eukaryotes. While much effort has been invested in understanding the enzymes that produce and consume these molecules, central aspects for how phosphoinositide production is controlled and functionally partitioned remain unresolved and largely unappreciated. It is in this regard that phosphatidylinositol (PtdIns) transfer proteins (PITPs) are emerging as central regulators of the functional channeling of phosphoinositide pools produced on demand for specific signaling purposes. The physiological significance of these proteins is amply demonstrated by the consequences that accompany deficits in individual PITPs. Although the biological problem is fascinating, and of direct relevance to disease, PITPs remain largely uncharacterized. Herein, we discuss our perspectives regarding what is known about how PITPs work as molecules, and highlight progress in our understanding of how PITPs are integrated into cellular physiology. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Aby Grabon
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Danish Khan
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Vytas A Bankaitis
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
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30
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Miller MB, Vishwanatha KS, Mains RE, Eipper BA. An N-terminal Amphipathic Helix Binds Phosphoinositides and Enhances Kalirin Sec14 Domain-mediated Membrane Interactions. J Biol Chem 2015; 290:13541-55. [PMID: 25861993 DOI: 10.1074/jbc.m115.636746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Indexed: 11/06/2022] Open
Abstract
Previous studies revealed an essential role for the lipid-binding Sec14 domain of kalirin (KalSec14), but its mechanism of action is not well understood. Because alternative promoter usage appends unique N-terminal peptides to the KalSec14 domain, we used biophysical, biochemical, and cell biological approaches to examine the two major products, bKalSec14 and cKalSec14. Promoter B encodes a charged, unstructured peptide, whereas promoter C encodes an amphipathic helix (Kal-C-helix). Both bKalSec14 and cKalSec14 interacted with lipids in PIP strip and liposome flotation assays, with significantly greater binding by cKalSec14 in both assays. Disruption of the hydrophobic face of the Kal-C-helix in cKalSec14KKED eliminated its increased liposome binding. Although cKalSec14 showed significantly reduced binding to liposomes lacking phosphatidylinositol phosphates or cholesterol, liposome binding by bKalSec14 and cKalSec14KKED was not affected. When expressed in AtT-20 cells, bKalSec14-GFP was diffusely localized, whereas cKalSec14-GFP localized to the trans-Golgi network and secretory granules. The amphipathic C-helix was sufficient for this localization. When AtT-20 cells were treated with a cell-permeant derivative of the Kal-C-helix (Kal-C-helix-Arg9), we observed increased secretion of a product stored in mature secretory granules, with no effect on basal secretion; a cell-permeant control peptide (Kal-C-helixKKED-Arg9) did not have this effect. Through its ability to control expression of a novel, phosphoinositide-binding amphipathic helix, Kalrn promoter usage is expected to affect function.
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Affiliation(s)
| | | | | | - Betty A Eipper
- From the Departments of Neuroscience and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut 06030
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31
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Zingg JM, Azzi A, Meydani M. Induction of VEGF Expression by Alpha-Tocopherol and Alpha-Tocopheryl Phosphate via PI3Kγ/PKB and hTAP1/SEC14L2-Mediated Lipid Exchange. J Cell Biochem 2015; 116:398-407. [DOI: 10.1002/jcb.24988] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 09/26/2014] [Indexed: 12/16/2022]
Affiliation(s)
- Jean-Marc Zingg
- Vascular Biology Laboratory; JM USDA-Human Nutr. Res. Ctr. On Aging; Tufts University; Boston MA 02111 USA
| | - Angelo Azzi
- Vascular Biology Laboratory; JM USDA-Human Nutr. Res. Ctr. On Aging; Tufts University; Boston MA 02111 USA
| | - Mohsen Meydani
- Vascular Biology Laboratory; JM USDA-Human Nutr. Res. Ctr. On Aging; Tufts University; Boston MA 02111 USA
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32
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Fayngerts SA, Wu J, Oxley CL, Liu X, Vourekas A, Cathopoulis T, Wang Z, Cui J, Liu S, Sun H, Lemmon MA, Zhang L, Shi Y, Chen YH. TIPE3 is the transfer protein of lipid second messengers that promote cancer. Cancer Cell 2014; 26:465-78. [PMID: 25242044 PMCID: PMC4198483 DOI: 10.1016/j.ccr.2014.07.025] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/29/2014] [Accepted: 07/28/2014] [Indexed: 02/04/2023]
Abstract
More than half of human cancers have aberrantly upregulated phosphoinositide signals; yet how phospholipid signals are controlled during tumorigenesis is not fully understood. We report here that TIPE3 (TNFAIP8L3) is the transfer protein of phosphoinositide second messengers that promote cancer. High-resolution crystal structure of TIPE3 shows a large hydrophobic cavity that is occupied by a phospholipid-like molecule. TIPE3 preferentially captures and shuttles two lipid second messengers, i.e., phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate, and increases their levels in the plasma membrane. Notably, human cancers have markedly upregulated TIPE3 expression. Knocking out TIPE3 diminishes tumorigenesis, whereas enforced TIPE3 expression enhances it in vivo. Thus, the function and metabolism of phosphoinositide second messengers are controlled by a specific transfer protein during tumorigenesis.
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Affiliation(s)
- Svetlana A Fayngerts
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jianping Wu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Camilla L Oxley
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xianglan Liu
- Institute of Immunology, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Anastassios Vourekas
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Terry Cathopoulis
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhaojun Wang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jian Cui
- Institute of Immunology, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Suxia Liu
- Institute of Immunology, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Honghong Sun
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark A Lemmon
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lining Zhang
- Institute of Immunology, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Yigong Shi
- School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Youhai H Chen
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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33
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Zingg JM, Libinaki R, Meydani M, Azzi A. Modulation of phosphorylation of tocopherol and phosphatidylinositol by hTAP1/SEC14L2-mediated lipid exchange. PLoS One 2014; 9:e101550. [PMID: 24983950 PMCID: PMC4077815 DOI: 10.1371/journal.pone.0101550] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/09/2014] [Indexed: 11/18/2022] Open
Abstract
The vitamin E derivative, alpha-tocopheryl phosphate (αTP), is detectable in cultured cells, plasma and tissues in small amounts, suggesting the existence of enzyme(s) with α-tocopherol (αT) kinase activity. Here, we characterize the production of αTP from αT and [γ-32P]-ATP in primary human coronary artery smooth muscle cells (HCA-SMC) using separation by thin layer chromatography (TLC) and subsequent analysis by Ultra Performance Liquid Chromatography (UPLC). In addition to αT, although to a lower amount, also γT is phosphorylated. In THP-1 monocytes, γTP inhibits cell proliferation and reduces CD36 scavenger receptor expression more potently than αTP. Both αTP and γTP activate the promoter of the human vascular endothelial growth factor (VEGF) gene with similar potency, whereas αT and γT had no significant effect. The recombinant human tocopherol associated protein 1 (hTAP1, hSEC14L2) binds both αT and αTP and stimulates phosphorylation of αT possibly by facilitating its transport and presentation to a putative αT kinase. Recombinant hTAP1 reduces the in vitro activity of the phosphatidylinositol-3-kinase gamma (PI3Kγ) indicating the formation of a stalled/inactive hTAP1/PI3Kγ heterodimer. The addition of αT, βT, γT, δT or αTP differentially stimulates PI3Kγ, suggesting facilitated egress of sequestered PI from hTAP1 to the enzyme. It is suggested that the continuous competitive exchange of different lipophilic ligands in hTAPs with cell enzymes and membranes may be a way to make these lipophiles more accessible as substrates for enzymes and as components of specific membrane domains.
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Affiliation(s)
- Jean-Marc Zingg
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. On Aging, Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
| | - Roksan Libinaki
- Dept. Biochem. and Mol. Biology, Monash University, Melbourne, VIC, Australia
| | - Mohsen Meydani
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. On Aging, Tufts University, Boston, Massachusetts, United States of America
| | - Angelo Azzi
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. On Aging, Tufts University, Boston, Massachusetts, United States of America
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34
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Ren J, Pei-Chen Lin C, Pathak MC, Temple BRS, Nile AH, Mousley CJ, Duncan MC, Eckert DM, Leiker TJ, Ivanova PT, Myers DS, Murphy RC, Brown HA, Verdaasdonk J, Bloom KS, Ortlund EA, Neiman AM, Bankaitis VA. A phosphatidylinositol transfer protein integrates phosphoinositide signaling with lipid droplet metabolism to regulate a developmental program of nutrient stress-induced membrane biogenesis. Mol Biol Cell 2014; 25:712-27. [PMID: 24403601 PMCID: PMC3937096 DOI: 10.1091/mbc.e13-11-0634] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/10/2013] [Accepted: 12/23/2013] [Indexed: 12/31/2022] Open
Abstract
Lipid droplet (LD) utilization is an important cellular activity that regulates energy balance and release of lipid second messengers. Because fatty acids exhibit both beneficial and toxic properties, their release from LDs must be controlled. Here we demonstrate that yeast Sfh3, an unusual Sec14-like phosphatidylinositol transfer protein, is an LD-associated protein that inhibits lipid mobilization from these particles. We further document a complex biochemical diversification of LDs during sporulation in which Sfh3 and select other LD proteins redistribute into discrete LD subpopulations. The data show that Sfh3 modulates the efficiency with which a neutral lipid hydrolase-rich LD subclass is consumed during biogenesis of specialized membrane envelopes that package replicated haploid meiotic genomes. These results present novel insights into the interface between phosphoinositide signaling and developmental regulation of LD metabolism and unveil meiosis-specific aspects of Sfh3 (and phosphoinositide) biology that are invisible to contemporary haploid-centric cell biological, proteomic, and functional genomics approaches.
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Affiliation(s)
- Jihui Ren
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Coney Pei-Chen Lin
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Manish C. Pathak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-4250
| | - Brenda R. S. Temple
- R. L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7260
| | - Aaron H. Nile
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Carl J. Mousley
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Mara C. Duncan
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Debra M. Eckert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650
| | - Thomas J. Leiker
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80045-0511
| | - Pavlina T. Ivanova
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - David S. Myers
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - Robert C. Murphy
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80045-0511
| | - H. Alex Brown
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - Jolien Verdaasdonk
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Kerry S. Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Eric A. Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-4250
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Vytas A. Bankaitis
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
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35
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Nile AH, Tripathi A, Yuan P, Mousley CJ, Suresh S, Wallace IM, Shah SD, Pohlhaus DT, Temple B, Nislow C, Giaever G, Tropsha A, Davis RW, St Onge RP, Bankaitis VA. PITPs as targets for selectively interfering with phosphoinositide signaling in cells. Nat Chem Biol 2014; 10:76-84. [PMID: 24292071 PMCID: PMC4059020 DOI: 10.1038/nchembio.1389] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 10/02/2013] [Indexed: 01/26/2023]
Abstract
Sec14-like phosphatidylinositol transfer proteins (PITPs) integrate diverse territories of intracellular lipid metabolism with stimulated phosphatidylinositol-4-phosphate production and are discriminating portals for interrogating phosphoinositide signaling. Yet, neither Sec14-like PITPs nor PITPs in general have been exploited as targets for chemical inhibition for such purposes. Herein, we validate what is to our knowledge the first small-molecule inhibitors (SMIs) of the yeast PITP Sec14. These SMIs are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs) and are effective inhibitors in vitro and in vivo. We further establish that Sec14 is the sole essential NPPM target in yeast and that NPPMs exhibit exquisite targeting specificities for Sec14 (relative to related Sec14-like PITPs), propose a mechanism for how NPPMs exert their inhibitory effects and demonstrate that NPPMs exhibit exquisite pathway selectivity in inhibiting phosphoinositide signaling in cells. These data deliver proof of concept that PITP-directed SMIs offer new and generally applicable avenues for intervening with phosphoinositide signaling pathways with selectivities superior to those afforded by contemporary lipid kinase-directed strategies.
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Affiliation(s)
- Aaron H. Nile
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
| | - Ashutosh Tripathi
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Peihua Yuan
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
| | - Carl J. Mousley
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
| | - Sundari Suresh
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Iain Michael Wallace
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Sweety D. Shah
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
| | - Denise Teotico Pohlhaus
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Brenda Temple
- R. L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260 USA
| | - Corey Nislow
- Faculty of Pharmaceutical Sciences,, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Guri Giaever
- Faculty of Pharmaceutical Sciences,, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Alexander Tropsha
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Ronald W. Davis
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Robert P. St Onge
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Vytas A. Bankaitis
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
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Cockcroft S, Garner K. Potential role for phosphatidylinositol transfer protein (PITP) family in lipid transfer during phospholipase C signalling. Adv Biol Regul 2013; 53:280-291. [PMID: 23916246 DOI: 10.1016/j.jbior.2013.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 06/02/2023]
Abstract
The hallmark of mammalian phosphatidylinositol transfer proteins (PITPs) is to transfer phosphatidylinositol between membrane compartments. In the mammalian genome, there are three genes that code for soluble PITP proteins, PITPα, PITPβ and RdgBβ and two genes that code for membrane-associated multi-domain proteins (RdgBαI and II) containing a PITP domain. PITPα and PITPβ constitute Class I PITPs whilst the RdgB proteins constitute Class II proteins based on sequence analysis. The PITP domain of both Class I and II can sequester one molecule of phosphatidylinositol (PI) in its hydrophobic cavity. Therefore, in principle, PITPs are therefore ideally poised to couple phosphatidylinositol delivery to the PI kinases for substrate provision for phospholipases C during cell activation. Since phosphatidylinositol (4,5)bisphosphate plays critical roles in cells, particularly at the plasma membrane, where it is a substrate for both phospholipase C and phosphoinositide-3-kinases as well as required as an intact lipid to regulate ion channels and the actin cytoskeleton, homeostatic mechanisms to maintain phosphatidylinositol(4,5)bisphosphate levels are vital. To maintain phosphatidylinositol levels, phospholipase C activation inevitably leads to the resynthesis of PI at the endoplasmic reticulum where the enzymes are located. Phosphatidic acid generated at the plasma membrane during phospholipase C activation needs to move to the ER for conversion to PI and here we provide evidence that Class II PITPs are also able to bind and transport phosphatidic acid. Thus RdgB proteins could couple PA and PI transport bidirectionally during phospholipase C signalling.
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Affiliation(s)
- Shamshad Cockcroft
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK.
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Kono N, Ohto U, Hiramatsu T, Urabe M, Uchida Y, Satow Y, Arai H. Impaired -TTP-PIPs Interaction Underlies Familial Vitamin E Deficiency. Science 2013; 340:1106-10. [DOI: 10.1126/science.1233508] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Abstract
The striking morphology of the Golgi complex has fascinated cell biologists since its discovery over 100 years ago. Yet, despite intense efforts to understand how membrane flow relates to Golgi form and function, this organelle continues to baffle cell biologists and biochemists alike. Fundamental questions regarding Golgi function, while hotly debated, remain unresolved. Historically, Golgi function has been described from a protein-centric point of view, but we now appreciate that conceptual frameworks for how lipid metabolism is integrated with Golgi biogenesis and function are essential for a mechanistic understanding of this fascinating organelle. It is from a lipid-centric perspective that we discuss the larger question of Golgi dynamics and membrane trafficking. We review the growing body of evidence for how lipid metabolism is integrally written into the engineering of the Golgi system and highlight questions for future study.
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Affiliation(s)
- Vytas A Bankaitis
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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Bankaitis VA, Ile KE, Nile AH, Ren J, Ghosh R, Schaaf G. Thoughts on Sec14-like nanoreactors and phosphoinositide signaling. Adv Biol Regul 2012; 52:115-21. [PMID: 22776890 DOI: 10.1016/j.jbior.2011.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 11/11/2011] [Indexed: 10/28/2022]
Affiliation(s)
- Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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Ghosh R, Bankaitis VA. Phosphatidylinositol transfer proteins: negotiating the regulatory interface between lipid metabolism and lipid signaling in diverse cellular processes. Biofactors 2011; 37:290-308. [PMID: 21915936 DOI: 10.1002/biof.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphoinositides represent only a small percentage of the total cellular lipid pool. Yet, these molecules play crucial roles in diverse intracellular processes such as signal transduction at membrane-cytosol interface, regulation of membrane trafficking, cytoskeleton organization, nuclear events, and the permeability and transport functions of the membrane. A central principle in such lipid-mediated signaling is the appropriate coordination of these events. Such an intricate coordination demands fine spatial and temporal control of lipid metabolism and organization, and consistent mechanisms for specifically coupling these parameters to dedicated physiological processes. In that regard, recent studies have identified Sec14-like phosphatidylcholine transfer protein (PITPs) as "coincidence detectors," which spatially and temporally link the diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. The integral role of PITPs in eukaryotic signal transduction design is amply demonstrated by the mammalian diseases associated with the derangements in the function of these proteins, to stress response and developmental regulation in plants, to fungal dimorphism and pathogenicity, to membrane trafficking in yeast, and higher eukaryotes. This review updates the recent advances made in the understanding of how these proteins, specifically PITPs of the Sec14-protein superfamily, operate at the molecular level and further describes how this knowledge has advanced our perception on the diverse biological functions of PITPs.
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Affiliation(s)
- Ratna Ghosh
- Lineberger Comprehensive Cancer Center, Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27526-7090, USA.
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