5mk0
From Proteopedia
Crystal structure of the His Domain Protein Tyrosine Phosphatase (HD-PTP/PTPN23) Bro1 domain (Endofin peptide complex)
Structural highlights
Function[PTN23_HUMAN] Plays a role in sorting of endocytic ubiquitinated cargos into multivesicular bodies (MVBs) via its interaction with the ESCRT-I complex (endosomal sorting complex required for transport I), and possibly also other ESCRT complexes. May act as a negative regulator of Ras-mediated mitogenic activity. Plays a role in ciliogenesis.[1] [2] [3] [ZFY16_HUMAN] May be involved in regulating membrane trafficking in the endosomal pathway. Overexpression induces endosome aggregation. Required to target TOM1 to endosomes.[4] [5] Publication Abstract from PubMedSARA and endofin are endosomal adaptor proteins that drive Smad phosphorylation by ligand-activated transforming growth factor beta/bone morphogenetic protein (TGFbeta/BMP) receptors. We show in this study that SARA and endofin also recruit the tumor supressor HD-PTP, a master regulator of endosomal sorting and ESCRT-dependent receptor downregulation. High-affinity interactions occur between the SARA/endofin N termini, and the conserved hydrophobic region in the HD-PTP Bro1 domain that binds CHMP4/ESCRT-III. CHMP4 engagement is a universal feature of Bro1 proteins, but SARA/endofin binding is specific to HD-PTP. Crystallographic structures of HD-PTPBro1 in complex with SARA, endofin, and three CHMP4 isoforms revealed that all ligands bind similarly to the conserved site but, critically, only SARA/endofin interact at a neighboring pocket unique to HD-PTP. The structures, together with mutagenesis and binding analysis, explain the high affinity and specific binding of SARA/endofin, and why they compete so effectively with CHMP4. Our data invoke models for how endocytic regulation of TGFbeta/BMP signaling is controlled. Structural Basis for Specific Interaction of TGFbeta Signaling Regulators SARA/Endofin with HD-PTP.,Gahloth D, Levy C, Walker L, Wunderley L, Mould AP, Taylor S, Woodman P, Tabernero L Structure. 2017 Jul 5;25(7):1011-1024.e4. doi: 10.1016/j.str.2017.05.005. Epub, 2017 Jun 8. PMID:28602823[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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