LAIR1 (CD305) Proteins

Protein Information

CD305, also known as LAIR1, is a type I transmembrane glycoprotein with an extracellular Ig-like domain and two intracellular ITIMs. It is expressed on a wide range of immune cells, including T, NK, and B cells, monocytes, dendritic cells, eosinophils, basophils, and mast cells. In humans, CD305 is also present on CD34+ hematopoietic progenitor cells and thymocytes. Several isoforms exist due to alternative splicing, with expression varying between cell types. CD305 functions as an inhibitory receptor, playing a key role in regulating immune responses. It blocks cytokine-mediated signaling, cell proliferation, and apoptosis. In NK, B, and T cells, CD305 modulates cytolytic functions and cytokine production, down-regulating IL2 and IFNG in CD4+ T cells while inducing transforming growth factor beta. In B cells, it reduces IgG and IgE production and decreases IL8, IL10, and TNF secretion. Activation of CD305 through tyrosine phosphorylation recruits phosphatases PTPN6 and PTPN11, although it may also function independently of SH2-containing phosphatases. It inhibits differentiation of peripheral blood precursors into dendritic cells and has been shown to induce apoptosis in myeloid leukemia cell lines. Collagens are identified as ligands for CD305, underscoring its role in immune regulation.

Synonyms

5133400O11Rik; BB115266; CD305; D7Bwg0421e; immunoglobulin heavy chain variable region; Lair1; Lair-1; leukocyte associated immunoglobulin like receptor 1; leukocyte-associated Ig-like receptor 1; leukocyte-associated Ig-like receptor-1; leukocyte-associated immunoglobulin-like receptor 1; rLAIR1