This entry represents the SH3 domain of proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1).Proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) belongs to the PCH family. It interacts with Wiskott-Aldrich syndrome protein (WASP) and PTPN12, which are important regulators of the cytoskeleton and cell migration, suggesting that PSTPIP1 functions in these pathways []. PSTPIP1 has been identified as a component of the leukocyte uropod that regulates endocytosis and cell migration []. It also controls extracellular matrix degradation and filopodia formation in macrophages []. It interacts with pyrin, a protein that associates with the cytoskeleton in myeloid/monocytic cells and modulates IL-1beta processing, NF-kappaB activation, and apoptosis []. Mutations in the PSTPIP1 gene have been linked to PAPA syndrome, an inflammatory disease [].Pombe Cdc15 homology (PCH) family proteins were initially identified as adaptor proteins involved in the regulation of cytokinesis and actin dynamics []. They share a similar domain architecture, consisting of an N-terminal FCH domain followed by a coiled coil (CC) region and by one or two C-terminal SH3 domains. However, in some family members the SH3 domain is absent (FCHO1, FCHO2 and PSTPIP2) or there are tissue-specific alternatively spliced isoforms with and without an SH3 domain (CIP4b, CIP4c, CIP4V, Fbp17b). PCH family proteins interact with receptors, adaptors, enzymes and structural proteins to regulate their localisation and activity. Through these interactions, PCH proteins regulate cell morphology and motility, organelle integrity, protein trafficking and the organisation of the actin cytoskeleton [].
