Tcr signaling pathway

TCR signaling pathway T cells are a subset of lymphocytes that play a crucial role in immune response. T-cell receptor (TCR) is a complex of integral membrane proteins on the surface of T cells, which takes part in the activation of T-cells in response to an antigen. Activation of TCR is triggered by major histocompatibility complex (MHC) molecules on antigen presenting cells (APC) that present antigen peptides to TCR complexes and promote a series of cellular signaling cascades, which eventually result in cellular proliferation, differentiation, cytokine production, and/or activation-induced cell death.

TCR/CD3 Complex TCR consists of six different polypeptide chains that form the TCR heterodimer responsible for ligand recognition.CD3 molecules (CD3ε, CD3γ, CD3δand CD3ζ), assembled together with the TCR heterodimer, possess a characteristic sequence motif for tyrosine phosphorylation, known as immuno-receptor tyrosine-based activation motifs (ITAMs). The TCR polypeptides themselves have very short cytoplasmic tails, and CD3 molecules are responsible for all the proximal signaling events mediation. TCR/CD3 complex interaction plays a central role in mediating cell recognition events ranging from receptor assembly, cell-surface expression, and signaling.

TCR Activation TCR activation is regulated by various co-stimulatory receptors. Many transmembrane receptors modulate specific elements of TCR signaling. CD28 is found to enhance TCR-induced proliferation and differentiation of naive T cells. Once binding with B7-1 or B7-2, CD28 provides the T-cell with an initial adhesion ability of approximating the T-Cell and APC membranes. Besides, CD45 regulates TCR signaling by modulating the phosphorylation state of the tyrosine kinases like Lck and Fyn, and antagonizing the inhibitory impact of inhibitory proteins, thereby favoring T-Cell activation. https://www.creative-diagnostics.com/tcr-signaling-pathway.htm