Fyb (Fyn binding protein) and the anchoring proteins SKAP55 and SKAP55-R (SKAP55-related protein) associate with the tyrosine kinase p59fyn. SKAP55 and SKAP55-R bind to Fyb through their SH3 domains and function as substrates for p59Fyn in resting T cells. SKAP55 contains an N-terminal pleckstrin homology domain and a SLCterminal SH3 domain binding motif of adjacent arginine and lysine residues followed by tandem tyrosines (i.e. RKxxYxxY). SKAP55-R, similar in overall structure to SKAP55, contains a coiled-coil N-terminal domain. SKAP55 associates with SLAP-130, another component of the Fyn complex, which plays a role in the regulation of signaling events initiated by lymphocyte antigen receptors leading up to T cell activation. The human SKAP55 gene maps to chromosome 17q21.32 and encodes a 359 amino acid protein.
Function:
May be involved in B-cell and macrophage adhesion processes. In B-cells, may act by coupling the B-cell receptor (BCR) to integrin activation. May play a role in src signaling pathway.
Subunit:
Homodimer (By similarity). Interacts with PTPNS1. Part of a complex consisting of SKAP2, FYB and PTPNS1. Part of a complex consisting of SKAP2, FYB and LILRB3. May interact with actin (By similarity). Interacts with FYB, which is required for SKAP2 protein stability. Interacts with LAT, GRB2, PTK2B and PRAM1. May interact with FYN, HCK and LYN. Interacts with FASLG.
Subcellular Location:
Cytoplasm.
Tissue Specificity:
Ubiquitously expressed. Present in platelets (at protein level).
Post-translational modifications:
Phosphorylated in resting platelets. Phosphorylated by FYN on Tyr-261 upon T-cell activation (Probable). Dephosphorylated on Tyr-75 by PTPN22.
Similarity:
Belongs to the SKAP family.
Contains 1 PH domain.
Contains 1 SH3 domain.
SWISS:
O75563
Gene ID:
8935
Database links:
Entrez Gene: 8935 Human
Entrez Gene: 616545 Cow
Entrez Gene: 54353 Mouse
Entrez Gene: 100171875 Orangutan
Entrez Gene: 155183 Rat
Omim: 605215 Human
SwissProt: Q32LP7 Cow
SwissProt: O75563 Human
SwissProt: Q3UND0 Mouse
SwissProt: Q5RDS2 Orangutan
SwissProt: Q920G0 Rat
Unigene: 200770 Human
Unigene: 610137 Human
Unigene: 221479 Mouse
Unigene: 392558 Mouse
Unigene: 162747 Rat
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