2oaj
From Proteopedia
Crystal structure of Sro7 from S. cerevisiae
Structural highlights
FunctionSRO7_YEAST Acts as an allosteric regulator of polarized exocytosis by promoting the targeted fusion of vesicles with the plasma membrane. Coordinates the spatial and temporal nature of both Rab-dependent tethering and SNARE-dependent membrane fusion of exocytic vesicles with the plasma membrane. Required for targeting of the sodium pumping ATPase ENA1 to the Cell Surface, thus being involved in maintenance of ion homeostasis in cells exposed to NaCl stress. May be involved in the targeting of the myosin proteins to their intrinsic pathways. Multicopy suppressor of RHO3. May also participate in the maintenance of cell polarity and bud growth.[1] [2] [3] [4] [5] [6] [7] 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 PubMedPolarized exocytosis requires coordination between the actin cytoskeleton and the exocytic machinery responsible for fusion of secretory vesicles at specific sites on the plasma membrane. Fusion requires formation of a complex between a vesicle-bound R-SNARE and plasma membrane Qa, Qb and Qc SNARE proteins. Proteins in the lethal giant larvae protein family, including lethal giant larvae and tomosyn in metazoans and Sro7 in yeast, interact with Q-SNAREs and are emerging as key regulators of polarized exocytosis. The crystal structure of Sro7 reveals two seven-bladed WD40 beta-propellers followed by a 60-residue-long 'tail', which is bound to the surface of the amino-terminal propeller. Deletion of the Sro7 tail enables binding to the Qbc SNARE region of Sec9 and this interaction inhibits SNARE complex assembly. The N-terminal domain of Sec9 provides a second, high-affinity Sro7 interaction that is unaffected by the tail. The results suggest that Sro7 acts as an allosteric regulator of exocytosis through interactions with factors that control the tail. Sequence alignments indicate that lethal giant larvae and tomosyn have a two-beta-propeller fold similar to that of Sro7, but only tomosyn appears to retain the regulatory tail. Structure of the yeast polarity protein Sro7 reveals a SNARE regulatory mechanism.,Hattendorf DA, Andreeva A, Gangar A, Brennwald PJ, Weis WI Nature. 2007 Mar 29;446(7135):567-71. PMID:17392788[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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