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Daboussi L, Costaguta G, Ghukasyan R, Payne GS. Conserved role for Gga proteins in phosphatidylinositol 4-kinase localization to the trans-Golgi network. Proc Natl Acad Sci U S A 2017; 114:3433-3438. [PMID: 28289207 PMCID: PMC5380026 DOI: 10.1073/pnas.1615163114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphoinositides serve as key membrane determinants for assembly of clathrin coat proteins that drive formation of clathrin-coated vesicles. At the trans-Golgi network (TGN), phosphatidylinositol 4-phosphate (PtdIns4P) plays important roles in recruitment of two major clathrin adaptors, Gga (Golgi-localized, gamma-adaptin ear homology, Arf-binding) proteins and the AP-1 (assembly protein-1) complex. The molecular mechanisms that mediate localization of phosphatidylinositol kinases responsible for synthesis of PtdIns4P at the TGN are not well characterized. We identify two motifs in the yeast phosphatidylinositol 4-kinase, Pik1, which are required for binding to the VHS domain of Gga2. Mutations in these motifs that inhibit Gga2-VHS binding resulted in reduced Pik1 localization and delayed accumulation of PtdIns4P and recruitment of AP-1 to the TGN. The Pik1 homolog in mammals, PI4KIIIβ, interacted preferentially with the VHS domain of GGA2 compared with VHS domains of GGA1 and GGA3. Depletion of GGA2, but not GGA1 or GGA3, specifically affected PI4KIIIβ localization. These results reveal a conserved role for Gga proteins in regulating phosphatidylinositol 4-kinase function at the TGN.
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Affiliation(s)
- Lydia Daboussi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095
| | - Giancarlo Costaguta
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095
| | - Razmik Ghukasyan
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095
| | - Gregory S Payne
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095
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De M, Oleskie AN, Ayyash M, Dutta S, Mancour L, Abazeed ME, Brace EJ, Skiniotis G, Fuller RS. The Vps13p-Cdc31p complex is directly required for TGN late endosome transport and TGN homotypic fusion. J Cell Biol 2017; 216:425-439. [PMID: 28122955 PMCID: PMC5294781 DOI: 10.1083/jcb.201606078] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/04/2016] [Accepted: 01/11/2017] [Indexed: 01/09/2023] Open
Abstract
VPS13 proteins are widely conserved in eukaryotes and associated with human neurodegenerative and neurodevelopmental diseases. De et al. describe the lipid specificity and structure of yeast Vps13p, providing insight into its role in both TGN late endosome transport and TGN homotypic fusion. Yeast VPS13 is the founding member of a eukaryotic gene family of growing interest in cell biology and medicine. Mutations in three of four human VPS13 genes cause autosomal recessive neurodegenerative or neurodevelopmental disease, making yeast Vps13p an important structural and functional model. Using cell-free reconstitution with purified Vps13p, we show that Vps13p is directly required both for transport from the trans-Golgi network (TGN) to the late endosome/prevacuolar compartment (PVC) and for TGN homotypic fusion. Vps13p must be in complex with the small calcium-binding protein Cdc31p to be active. Single-particle electron microscopic analysis of negatively stained Vps13p indicates that this 358-kD protein is folded into a compact rod-shaped density (20 × 4 nm) with a loop structure at one end with a circular opening ∼6 nm in diameter. Vps13p exhibits ATP-stimulated binding to yeast membranes and specific interactions with phosphatidic acid and phosphorylated forms of phosphatidyl inositol at least in part through the binding affinities of conserved N- and C-terminal domains.
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Affiliation(s)
- Mithu De
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Austin N Oleskie
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109.,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Mariam Ayyash
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Somnath Dutta
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109.,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Liliya Mancour
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109.,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Mohamed E Abazeed
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109.,Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Eddy J Brace
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Georgios Skiniotis
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109.,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Robert S Fuller
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109
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