LAG-3 Protein, Rat (HEK293, His)

LAG-3 (Lymphocyte activation gene 3) protein serves as an inhibitory receptor on antigen-activated T-cells, delivering inhibitory signals upon binding to ligands such as FGL1, a major contributor to LAG3's T-cell inhibitory function. Upon T-cell receptor (TCR) engagement, LAG3 associates with CD3-TCR in the immunological synapse, directly impeding T-cell activation. LAG3 may collaborate with PDCD1/PD-1, potentially acting as a coreceptor for PD-1, to inhibit antigen-specific T-cell activation. This protein negatively regulates the proliferation, activation, effector function, and homeostasis of both CD8(+) and CD4(+) T-cells. Furthermore, LAG-3 plays a pivotal role in immune tolerance, being constitutively expressed on a subset of regulatory T-cells (Tregs), contributing to their suppressive function. Additionally, LAG-3 acts as a negative regulator of plasmacytoid dendritic cell (pDCs) activation and exhibits interactions with MHC class II (MHC-II), although the precise role of MHC-II binding remains unclear. LAG-3 may function as a ligand for MHC class II on antigen-presenting cells (APC), potentially promoting APC activation/maturation and driving Th1 immune responses.