G6B is a member of the immunoglobulin (Ig) superfamily with 241aa and is a glycosylated, plasma membrane-bound cell surface receptor, but soluble isoforms encoded by some transcript variants have been found in the endoplasmic reticulum and Golgi before being secreted. Multiple transcript variants encoding different isoforms have been reported. RT-PCR, Western Blot, and flow cytometric analyses suggest that G6B is usually expressed on platelets and cross linking of G6B inhibits platelet aggregation and activation in a calcium-independent manner by agonists such as ADP and collagen-related peptide. G6B is an inhibitory surface receptor on platelets and may be an antithrombotic drug target. Isoform B is a putative inhibitory receptor. Isoform A may be its activating counterpart. It is known to bind to heparin. G6B is usually expressed in a restricted set of hematopoietic cell lines like K562, Molt4 and Jurkat and not detected in the cell lines like U937, Raji, Tk, HeLa, NKL, NK62 and YT.