Proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), also known as MAYP, belongs to the PCH (Pombe Cdc15 homology) family of proteins involved in the regulation of actin-related functions, including cell adhesion and motility []. In mice, it regulates F-actin bundling and enhances filopodia formation and motility in macrophages []. It may play an anti-inflammatory role in macrophages [].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 [].
F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization []. Proline-Serine-Threonine Phosphatase-Interacting Protein 2 (PSTPIP2) is mostly expressed in hematopoietic cells but is also expressed in the brain. It is involvedin regulating cell adhesion and motility []. Mutations in the gene encoding murine PSTPIP2 can cause autoinflammatory disorders such as chronic multifocal osteomyelitis and macrophage autoinflammatory disease []. PSTPIP2 contains an N-terminal F-BAR domain and lacks the PEST motifs and SH3 domain that are found in PSTPIP1. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules [].
