Tyrosin-protein kinase Lck

1lkkA SH2 domain

Tyrosine-protein kinase Lck

Tyrosine-protein kinase Lck, also known as Lck or lymphocyte-specific protein-tyrosine kinase, is an enzyme that in humans is encoded by the LCK gene. Lck is a member of the Src family of protein kinases and plays a crucial role in T-cell development and activation.

Structure

Lck consists of several structural domains, including an N-terminal unique domain, Src homology 3 (SH3) domain, Src homology 2 (SH2) domain, and a C-terminal kinase domain. The SH2 and SH3 domains are involved in protein-protein interactions, while the kinase domain is responsible for phosphorylating target proteins on tyrosine residues.

Function

Lck is primarily expressed in T-cells and is essential for T-cell receptor (TCR) signaling. Upon TCR engagement, Lck is recruited to the TCR complex where it phosphorylates key signaling molecules, leading to the activation of downstream signaling pathways. Lck also plays a role in thymocyte development and selection.

Regulation

The activity of Lck is tightly regulated to ensure proper T-cell function. Phosphorylation of specific tyrosine residues within Lck can either activate or inhibit its kinase activity. Additionally, binding of the SH2 domain to specific phosphotyrosine motifs can modulate Lck activity.

Clinical significance

Dysregulation of Lck activity has been implicated in various diseases, including autoimmune disorders and certain types of cancer. Targeting Lck with specific inhibitors has emerged as a potential therapeutic strategy for these conditions.

See also

• Src family kinases
• T-cell receptor
• Protein kinase