Lck, SH3 domain (IPR035749)

Short name: Lck_SH3

Overlapping homologous superfamilies

Domain relationships

  • SH3 domain (IPR001452)
    • Lck, SH3 domain (IPR035749)


Lck is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. Lck is expressed in T-cells and natural killer cells. It plays a critical role in T-cell maturation, activation, and T-cell receptor (TCR) signaling [PMID: 17998336, PMID: 17118402]. Lck phosphorylates ITAM (immunoreceptor tyr activation motif) sequences on several subunits of TCRs, leading to the activation of different second messenger cascades. Phosphorylated ITAMs serve as binding sites for other signaling factor such as Syk and ZAP-70, leading to their activation and propagation of downstream events [PMID: 16257509]. In addition, Lck regulates drug-induced apoptosis by interfering with the mitochondrial death pathway. The apototic role of Lck is independent of its primary function in T-cell signaling [PMID: 21983898].

Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction [PMID: 17905674, PMID: 18563293].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.