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Crystal Structure of STAM2 SH3 domain in complex with a UBPY-derived peptide
Structural highlights
FunctionSTAM2_MOUSE Involved in intracellular signal transduction mediated by cytokines and growth factors. Upon IL-2 and GM-CSL stimulation, it plays a role in signaling leading to DNA synthesis and MYC induction. May also play a role in T-cell development. Involved in down-regulation of receptor tyrosine kinase via multivesicular body (MVBs) when complexed with HGS (ESCRT-0 complex). The ESCRT-0 complex binds ubiquitin and acts as sorting machinery that recognizes ubiquitinated receptors and transfers them to further sequential lysosomal sorting/trafficking processes (By similarity).[1] 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 PubMedAlthough some exceptional motifs have been identified, it is well known that the PXXP motif is the motif of ligand proteins generally recognized by the Src homology 3 (SH3) domain. SH3-ligand interactions are usually weak, with ordinary KD approximately 10 microM. The structural basis for a tight and specific association (KD = 0.24 microm) between Gads SH3 and a novel motif, PX(V/I)(D/N)RXXKP, was revealed in a previous structural analysis of the complex formed between them. In this paper, we report the crystal structure of the signal transducing adaptor molecule-2 (STAM2) SH3 domain in complex with a peptide with a novel motif derived from a ligand protein, UBPY. The derived KD value for this complex is 27 microM. The notable difference in affinity for these parallel complexes may be explained because the STAM2 SH3 structure does not provide a specificity pocket for binding, whereas the Gads SH3 structure does. Instead, the structure of STAM2 SH3 is analogous to that of Grb2 SH3 which, in addition to normal PXXP ligands, has also been shown to moderately recognize the novel motif discussed herein. Thus, the extremely tight interaction observed between Gads SH3 and the novel motif is caused not by an innate ability of the novel motif but rather by an evolutionary change in the Gads SH3 domain. Instead, SH3 domains of STAM2 and Grb2 retain the moderate characteristics of recognizing their ligand proteins like other SH3 domains for appropriate transient interactions between signaling molecules. Structural insight into modest binding of a non-PXXP ligand to the signal transducing adaptor molecule-2 Src homology 3 domain.,Kaneko T, Kumasaka T, Ganbe T, Sato T, Miyazawa K, Kitamura N, Tanaka N J Biol Chem. 2003 Nov 28;278(48):48162-8. Epub 2003 Sep 16. PMID:13129930[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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