Lck (pY505) Pure 4/Lck (pY505) 50ug

Protein tyrosine phosphorylation is an essential step in the signal transduction cascade leading to T cell antigen receptor (TCR) activation. Lck

is a protein kinase and a member of the src family of cytoplasmic protein-tyrosine kinases (PTKs). Members of this family have several

common features: 1) unique N-terminal domains, 2) attachment to cellular membranes through a myristylated N-terminus, and 3) homologous

SH2, SH3, and catalytic domains. The unique N-terminal domain of Lck interacts with the cytoplasmic tails of the CD4 and CD8 cell surface

glycoproteins. CD4 and CD8 bind to surface MHC class II and class I molecules, respectively. Lck is regulated by both kinases and

phosphatases. Autophosphorylation at Y394 leads to conformational changes in the catalytic domain, which induces kinase activity.

Repression of Lck occurs via phosphorylation at Y505, located near the carboxy-terminus. Phosphorylation of this tyrosine site is mediated by

the Csk family of PTKs. Upon phosphorylation at this site, Lck associates with the SH2 domain in the amino-terminus, thus keeping the

protein biologically inactive. Lck activity and regulation is critical for activation and development of T cells.

1.Since applications vary, each investigator should titrate the reagent to obtain optimal results.

2.Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.