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Crystal structure of Saccharomyces cerevisiae Vps15 WD repeat domainCrystal structure of Saccharomyces cerevisiae Vps15 WD repeat domain
Structural highlights
Function[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.[1] [2] [3] [4] [5] [6] [7] [8] [9] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedG protein-coupled receptors mediate cellular responses to a wide variety of stimuli, including taste, light, and neurotransmitters. In the yeast Saccharomyces cerevisiae, activation of the pheromone pathway triggers events leading to mating. The view had long been held that the G protein-mediated signal occurs principally at the plasma membrane. Recently, it has been shown that the G protein alpha subunit Gpa1 can promote signaling at endosomes and requires two components of the sole phosphatidylinositol-3-kinase in yeast, Vps15 and Vps34. Vps15 contains multiple WD repeats and also binds to Gpa1 preferentially in the GDP-bound state; these observations led us to hypothesize that Vps15 may function as a G protein beta subunit at the endosome. Here we show an X-ray crystal structure of the Vps15 WD domain that reveals a seven-bladed propeller resembling that of typical Gbeta subunits. We show further that the WD domain is sufficient to bind Gpa1 as well as to Atg14, a potential Ggamma protein that exists in a complex with Vps15. The Vps15 kinase domain together with the intermediate domain (linking the kinase and WD domains) also contributes to Gpa1 binding and is necessary for Vps15 to sustain G protein signaling. These findings reveal that the Vps15 Gbeta-like domain serves as a scaffold to assemble Gpa1 and Atg14, whereas the kinase and intermediate domains are required for proper signaling at the endosome. Structure and function of Vps15 in the endosomal G protein signaling pathway.,Heenan EJ, Vanhooke JL, Temple BR, Betts L, Sondek JE, Dohlman HG Biochemistry. 2009 Jul 14;48(27):6390-401. PMID:19445518[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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