| Structural highlights
Function
[VPS34_YEAST] Phosphatidylinositol 3-kinase required for cytoplasm to vacuole transport (Cvt) and autophagy as a part of the autophagy-specific VPS34 PI3-kinase complex I. This complex is essential to recruit the ATG8-phosphatidylinositol conjugate and the ATG12-ATG5 conjugate to the pre-autophagosomal structure. Also involved in endosome-to-Golgi retrograde transport as part of the VPS34 PI3-kinase complex II. This second complex is required for the endosome-to-Golgi retrieval of PEP1 and KEX2, and the recruitment of VPS5 and VPS7, two components of the retromer complex, to endosomal membranes (probably through the synthesis of a specific pool of phosphatidylinositol 3-phosphate recruiting the retromer to the endosomes). Its activation by VPS15 may lead to the phosphorylation of phosphatidylinositol in the sorting compartment membrane. Finally, it might also be involved in ethanol tolerance and cell wall integrity.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [VPS15_YEAST] Serine/threonine-protein kinase required for cytoplasm to vacuole transport (Cvt) and autophagy as a part of the autophagy-specific VPS34 PI3-kinase complex I. This complex is essential to recruit the ATG8-phosphatidylinositol conjugate and the ATG12-ATG5 conjugate to the pre-autophagosomal structure. Is also involved in endosome-to-Golgi retrograde transport as part of the VPS34 PI3-kinase complex II. This second complex is required for the endosome-to-Golgi retrieval of PEP1 and KEX2, and the recruitment of VPS5 and VPS7, two components of the retromer complex, to endosomal membranes (probably through the synthesis of a specific pool of phosphatidylinositol 3-phosphate recruiting the retromer to the endosomes). By regulating VPS34 kinase activity, VPS15 appears to be essential for the efficient delivery of soluble hydrolases to the yeast vacuole.[11] [12] [13] [14] [15] [16] [17] [18] [19]
Publication Abstract from PubMed
The phosphatidylinositol 3-kinase Vps34 is part of several protein complexes. The structural organization of heterotetrameric complexes is starting to emerge, but little is known about organization of additional accessory subunits that interact with these assemblies. Combining hydrogen-deuterium exchange mass spectrometry (HDX-MS), X-ray crystallography and electron microscopy (EM), we have characterized Atg38 and its human ortholog NRBF2, accessory components of complex I consisting of Vps15-Vps34-Vps30/Atg6-Atg14 (yeast) and PIK3R4/VPS15-PIK3C3/VPS34-BECN1/Beclin 1-ATG14 (human). HDX-MS shows that Atg38 binds the Vps30-Atg14 subcomplex of complex I, using mainly its N-terminal MIT domain and bridges the coiled-coil I regions of Atg14 and Vps30 in the base of complex I. The Atg38 C-terminal domain is important for localization to the phagophore assembly site (PAS) and homodimerization. Our 2.2 A resolution crystal structure of the Atg38 C-terminal homodimerization domain shows 2 segments of alpha-helices assembling into a mushroom-like asymmetric homodimer with a 4-helix cap and a parallel coiled-coil stalk. One Atg38 homodimer engages a single complex I. This is in sharp contrast to human NRBF2, which also forms a homodimer, but this homodimer can bridge 2 complex I assemblies.
Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex.,Ohashi Y, Soler N, Garcia Ortegon M, Zhang L, Kirsten ML, Perisic O, Masson GR, Burke JE, Jakobi AJ, Apostolakis AA, Johnson CM, Ohashi M, Ktistakis NT, Sachse C, Williams RL Autophagy. 2016 Sep 14:0. PMID:27630019[20]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kihara A, Noda T, Ishihara N, Ohsumi Y. Two distinct Vps34 phosphatidylinositol 3-kinase complexes function in autophagy and carboxypeptidase Y sorting in Saccharomyces cerevisiae. J Cell Biol. 2001 Feb 5;152(3):519-30. PMID:11157979
- ↑ Takahashi T, Shimoi H, Ito K. Identification of genes required for growth under ethanol stress using transposon mutagenesis in Saccharomyces cerevisiae. Mol Genet Genomics. 2001 Aug;265(6):1112-9. PMID:11523784
- ↑ Burda P, Padilla SM, Sarkar S, Emr SD. Retromer function in endosome-to-Golgi retrograde transport is regulated by the yeast Vps34 PtdIns 3-kinase. J Cell Sci. 2002 Oct 15;115(Pt 20):3889-900. PMID:12244127
- ↑ Herman PK, Emr SD. Characterization of VPS34, a gene required for vacuolar protein sorting and vacuole segregation in Saccharomyces cerevisiae. Mol Cell Biol. 1990 Dec;10(12):6742-54. PMID:2247081
- ↑ Auger KR, Carpenter CL, Cantley LC, Varticovski L. Phosphatidylinositol 3-kinase and its novel product, phosphatidylinositol 3-phosphate, are present in Saccharomyces cerevisiae. J Biol Chem. 1989 Dec 5;264(34):20181-4. PMID:2555343
- ↑ Robinson JS, Klionsky DJ, Banta LM, Emr SD. Protein sorting in Saccharomyces cerevisiae: isolation of mutants defective in the delivery and processing of multiple vacuolar hydrolases. Mol Cell Biol. 1988 Nov;8(11):4936-48. PMID:3062374
- ↑ Munn AL, Riezman H. Endocytosis is required for the growth of vacuolar H(+)-ATPase-defective yeast: identification of six new END genes. J Cell Biol. 1994 Oct;127(2):373-86. PMID:7929582
- ↑ Stack JH, Emr SD. Vps34p required for yeast vacuolar protein sorting is a multiple specificity kinase that exhibits both protein kinase and phosphatidylinositol-specific PI 3-kinase activities. J Biol Chem. 1994 Dec 16;269(50):31552-62. PMID:7989323
- ↑ Schu PV, Takegawa K, Fry MJ, Stack JH, Waterfield MD, Emr SD. Phosphatidylinositol 3-kinase encoded by yeast VPS34 gene essential for protein sorting. Science. 1993 Apr 2;260(5104):88-91. PMID:8385367
- ↑ Stack JH, Herman PK, Schu PV, Emr SD. A membrane-associated complex containing the Vps15 protein kinase and the Vps34 PI 3-kinase is essential for protein sorting to the yeast lysosome-like vacuole. EMBO J. 1993 May;12(5):2195-204. PMID:8387919
- ↑ Herman PK, Stack JH, DeModena JA, Emr SD. A novel protein kinase homolog essential for protein sorting to the yeast lysosome-like vacuole. Cell. 1991 Jan 25;64(2):425-37. PMID:1988155
- ↑ Robinson JS, Klionsky DJ, Banta LM, Emr SD. Protein sorting in Saccharomyces cerevisiae: isolation of mutants defective in the delivery and processing of multiple vacuolar hydrolases. Mol Cell Biol. 1988 Nov;8(11):4936-48. PMID:3062374
- ↑ Herman PK, Stack JH, Emr SD. A genetic and structural analysis of the yeast Vps15 protein kinase: evidence for a direct role of Vps15p in vacuolar protein delivery. EMBO J. 1991 Dec;10(13):4049-60. PMID:1756716
- ↑ Stack JH, Herman PK, Schu PV, Emr SD. A membrane-associated complex containing the Vps15 protein kinase and the Vps34 PI 3-kinase is essential for protein sorting to the yeast lysosome-like vacuole. EMBO J. 1993 May;12(5):2195-204. PMID:8387919
- ↑ Vida TA, Huyer G, Emr SD. Yeast vacuolar proenzymes are sorted in the late Golgi complex and transported to the vacuole via a prevacuolar endosome-like compartment. J Cell Biol. 1993 Jun;121(6):1245-56. PMID:8509446
- ↑ Stack JH, Emr SD. Vps34p required for yeast vacuolar protein sorting is a multiple specificity kinase that exhibits both protein kinase and phosphatidylinositol-specific PI 3-kinase activities. J Biol Chem. 1994 Dec 16;269(50):31552-62. PMID:7989323
- ↑ Nothwehr SF, Bryant NJ, Stevens TH. The newly identified yeast GRD genes are required for retention of late-Golgi membrane proteins. Mol Cell Biol. 1996 Jun;16(6):2700-7. PMID:8649377
- ↑ Kihara A, Noda T, Ishihara N, Ohsumi Y. Two distinct Vps34 phosphatidylinositol 3-kinase complexes function in autophagy and carboxypeptidase Y sorting in Saccharomyces cerevisiae. J Cell Biol. 2001 Feb 5;152(3):519-30. PMID:11157979
- ↑ Burda P, Padilla SM, Sarkar S, Emr SD. Retromer function in endosome-to-Golgi retrograde transport is regulated by the yeast Vps34 PtdIns 3-kinase. J Cell Sci. 2002 Oct 15;115(Pt 20):3889-900. PMID:12244127
- ↑ Ohashi Y, Soler N, Garcia Ortegon M, Zhang L, Kirsten ML, Perisic O, Masson GR, Burke JE, Jakobi AJ, Apostolakis AA, Johnson CM, Ohashi M, Ktistakis NT, Sachse C, Williams RL. Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex. Autophagy. 2016 Sep 14:0. PMID:27630019 doi:https://dx.doi.org/10.1080/15548627.2016.1226736
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