PSTPIP1

The protein encoded by this gene binds to the cytoplasmic tail of CD2, an effector of T cell activation and adhesion, negatively affecting CD2-triggered T cell activation. The encoded protein appears to be a scaffold protein and a regulator of the actin cytoskeleton. It has also been shown to bind ABL1, PTPN18, WAS, CD2AP, and PTPN12. Mutations in this gene are a cause of PAPA syndrome. [provided by RefSeq]

proline-serine-threonine phosphatase interacting protein 1

Involved in regulation of the actin cytoskeleton. May regulate WAS actin-bundling activity. Bridges the interaction between ABL1 and PTPN18 leading to ABL1 dephosphorylation. May play a role as a scaffold protein between PTPN12 and WAS and allow 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. Also has a role in innate immunity and the inflammatory response. Recruited to inflammasomes by MEFV. Induces formation of pyroptosomes, large supramolecular structures composed of oligomerized PYCARD dimers which form prior to inflammatory apoptosis. Binding to MEFV allows MEFV to bind to PYCARD and facilitates pyroptosome formation. Regulates endocytosis and cell migration in neutrophils.

Actin filament polymerizationManual Assertion Based On ExperimentIBA:GO_Central
Cell adhesionManual Assertion Based On ExperimentTAS:ProtInc
EndocytosisIEA:UniProtKB-KW
Inflammatory responseIEA:UniProtKB-KW
Innate immune responseIEA:UniProtKB-KW
Signal transductionManual Assertion Based On ExperimentTAS:ProtInc

Cytoplasm
Cell membrane
Cell projection, uropodium
Cytoplasm, cytoskeleton
Cytoplasm, perinuclear region
Cell projection, lamellipodium
Cleavage furrow
Mainly cytoplasmic in T-cells (PubMed:9857189).
Colocalizes in cluster with CD2 near the cell surface membrane in activated T-cells (PubMed:9857189).
In monocytes, forms a branched filamentous network in the cytoplasm (PubMed:19584923).
In transfected cells, forms relatively straight filaments radiating out from the nucleus (PubMed:19584923).
Filament formation requires an intact tubulin cytoskeleton (PubMed:19584923).
In migrating neutrophils, colocalizes with PIP5K1C and DNM2 to the trailing edge of the uropod in a actin-dependent manner (PubMed:18480402).
Colocalized with PTPN12 in the cytoplasm and the perinuclear region. During interphase, colocalizes with F-actin in the cortical cytoskeleton, lamellipodia, and stress fibers. In dividing cells, colocalizes with the F-actin rich cytokinetic cleavage furrow. Colocalized with CD2AP and WAS in the actin cytoskeleton within the cytoplasm. Colocalized with CD2, CD2AP and WAS at the site of T-cell:APC contact (By similarity).

PAPA syndrome (PAPAS):
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.

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 (By similarity).