3fze

Structure of the 'minimal scaffold' (ms) domain of Ste5 that cocatalyzes Fus3 phosphorylation by Ste7

spinqualitylabelsall models 3fze, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3fze is a 1 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: NUL3, STE5, YD8557.12, YDR103W (Saccharomyces cerevisiae) Resources: FirstGlance, OCA, RCSB, PDBsum Function [STE5_YEAST] Component of the pheromone signal transduction pathway. It mediates pheromone signals acting between STE20 and STE11. It is absolutely required for pheromone-induced transcription of FUS1. May play a role in cell-cycle arrest in response to pheromone. Publication Abstract from PubMed The scaffold protein Ste5 is required to properly direct signaling through the yeast mating pathway to the mitogen-activated protein kinase (MAPK), Fus3. Scaffolds are thought to function by tethering kinase and substrate in proximity. We find, however, that the previously identified Fus3-binding site on Ste5 is not required for signaling, suggesting an alternative mechanism controls Fus3's activation by the MAPKK Ste7. Reconstituting MAPK signaling in vitro, we find that Fus3 is an intrinsically poor substrate for Ste7, although the related filamentation MAPK, Kss1, is an excellent substrate. We identify and structurally characterize a domain in Ste5 that catalytically unlocks Fus3 for phosphorylation by Ste7. This domain selectively increases the k(cat) of Ste7-->Fus3 phosphorylation but has no effect on Ste7-->Kss1 phosphorylation. The dual requirement for both Ste7 and this Ste5 domain in Fus3 activation explains why Fus3 is selectively activated by the mating pathway and not by other pathways that also utilize Ste7. The Ste5 scaffold directs mating signaling by catalytically unlocking the Fus3 MAP kinase for activation.,Good M, Tang G, Singleton J, Remenyi A, Lim WA Cell. 2009 Mar 20;136(6):1085-97. PMID:19303851 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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