5g1e
The complex structure of syntenin-1 PDZ domain with c-terminal extension
Structural highlights
FunctionSDCB1_RAT Multifunctional adapter protein involved in diverse array of functions including trafficking of transmembrane proteins, neuro and immunomodulation, exosome biogenesis, and tumorigenesis. Positively regulates TGFB1-mediated SMAD2/3 activation and TGFB1-induced epithelial-to-mesenchymal transition (EMT) and cell migration in various cell types. May increase TGFB1 signaling by enhancing cell-surface expression of TGFR1 by preventing the interaction between TGFR1 and CAV1 and subsequent CAV1-dependent internalization and degradation of TGFR1. In concert with SDC1/4 and PDCD6IP, regulates exosome biogenesis. Regulates migration, growth, proliferation, and cell cycle progression in a variety of cancer types. In adherens junctions may function to couple syndecans to cytoskeletal proteins or signaling components. Seems to couple transcription factor SOX4 to the IL-5 receptor (IL5RA). May also play a role in vesicular trafficking. Seems to be required for the targeting of TGFA to the cell surface in the early secretory pathway.[UniProtKB:O00560] Publication Abstract from PubMedThe PDZ domain-containing scaffold protein, syntenin-1, binds to the transmembrane proteoglycan, syndecan-4, but the molecular mechanism/function of this interaction are unknown. Crystal structure analysis of syntenin-1/syndecan-4 cytoplasmic domains revealed that syntenin-1 forms a symmetrical pair of dimers anchored by a syndecan-4 dimer. The syndecan-4 cytoplasmic domain is a compact intertwined dimer with a symmetrical clamp shape and two antiparallel strands forming a cavity within the dimeric twist. The PDZ2 domain of syntenin-1 forms a direct antiparallel interaction with the syndecan-4 cytoplasmic domain, inhibiting the functions of syndecan-4 such as focal adhesion formation. Moreover, C-terminal region of syntenin-1 reveals an essential role for enhancing the molecular homodimerization. Mutation of key syntenin-1 residues involved in the syndecan-4 interaction or homodimer formation abolishes the inhibitory function of syntenin-1, as does deletion of the homodimerization-related syntenin-1 C-terminal domain. Syntenin-1, but not dimer-formation-incompetent mutants, rescued the syndecan-4-mediated inhibition of migration and pulmonary metastasis by B16F10 cells. Therefore, we conclude that syntenin-1 negatively regulates syndecan-4 function via oligomerization and/or syndecan-4 interaction, impacting cytoskeletal organization and cell migration. New structural insight of C-terminal region of Syntenin-1, enhancing the molecular dimerization and inhibitory function related on Syndecan-4 signaling.,Choi Y, Yun JH, Yoo J, Lee I, Kim H, Son HN, Kim IS, Yoon HS, Zimmermann P, Couchman JR, Cho HS, Oh ES, Lee W Sci Rep. 2016 Nov 10;6:36818. doi: 10.1038/srep36818. PMID:27830760[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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