gp49, also known as ILT3, gp49b1 or CD85k, is a 49 kD glycoprotein expressed on activated NK cells and myeloid cells. It structurally resembles killer inhibitory receptors (KIR). gp49B is a type I membrane protein belonging to the Ig superfamily and contains an immunoreceptor tyrosine-based inhibitory motif (ITIM), while gp49A is a truncated molecule without ITIM. Upon activation following interaction with integrin avb3, the cytoplasmic tail associates with SHP-1 and SHP-2, which results in downregulation of cell activation and cytokine production.