Involved in regulation of the actin cytoskeleton. May regulate the WAS actin-bundling activity. Bridges the interaction between ABL1 and PTPN18 leading to the ABL1 dephosphorylation. May play a role as a scaffold protein between PTPN12 and WAS and allows PTPN12 to dephosphorylate WAS. Has the potential to physically couple CD2 and CD2AP to WAS. Acts downstream of CD2 and CD2AP to recruit WAS to the T-cell:APC contact site so as to promote the actin polymerization required for synapse induction during T-cell activation (By similarity). Down-regulates CD2-stimulated adhesion through the coupling of PTPN12 to CD2.
Highly expressed in the peripheral blood leukocytes, granulocytes and monocytes, namely in T-cells and natural killer cells, and in spleen. Weakly expressed in the thymus, small intestine, lung and placenta.
Involvement in disease
Defects in PSTPIP1 are the cause of PAPA syndrome (PAPAS) [MIM:604416]; also known as pyogenic sterile arthritis, pyoderma gangrenosum and acne or familial recurrent arthritis (FRA). PAPAS is characterized by autosomal dominant inheritance of early onset, primarily affecting skin and joint tissues. Recurring inflammatory episodes lead to accumulation of sterile, pyogenic, neutrophil-rich material within the affected joints, ultimately resulting in significant destruction.
Contains 1 FCH domain. Contains 1 SH3 domain.
The coiled domain mediates interaction with PTPN18, PTPN12 and CD2AP. The SH3 domain mediates interaction with WAS and ABL1 (By similarity). The SH3 and coiled-coil domains are necessary for the interaction with MEFV.
Dephosphorylated on Tyr-345 by PTPN18, this event negatively regulates the association of PSTPIP1 with SH2 domain-containing proteins as tyrosine kinase. Phosphorylation of Tyr-345 is probably required for subsequent phosphorylation at other tyrosine residues. Phosphorylation is induced by activation of the EGFR and PDGFR in a ABL1 dependent manner. The phosphorylation regulates the interaction with WAS and with MEFV.
Cytoplasm. Cytoplasm > cytoskeleton. Cell projection > lamellipodium. Cytoplasm > perinuclear region. Cleavage furrow. Colocalized with the cortical actin cytoskeleton during interphase, lamellipodia and actin-rich cytokinetic cleavage furrow. Colocalized with WAS to filamentous structures within the cytoplasm. Colocalized with PTPN12 in the cytoplasm and the perinuclear region. Colocalized with CD2AP and WAS in the actin cytoskeleton. Colocalized with CD2, CD2AP and WAS at the site of T-cell:APC contact.