SIRPG Human

Signal-Regulatory Protein Gamma (SIRPγ) is a member of the signal-regulatory protein (SIRP) family, which belongs to the immunoglobulin superfamily. SIRPγ is a type I transmembrane glycoprotein that plays a crucial role in the regulation of immune responses. It is uniquely expressed on T lymphocytes and is involved in the integrin-independent adhesion of lymphocytes to antigen-presenting cells .

The preparation of human recombinant SIRPγ typically involves the expression of the protein in a suitable host system, such as Escherichia coli (E. coli). The gene encoding SIRPγ is cloned into an expression vector, which is then introduced into the host cells. The host cells are cultured under conditions that promote the expression of the recombinant protein. After sufficient expression, the cells are harvested, and the protein is purified using techniques such as affinity chromatography .

SIRPγ interacts with its physiological ligand, CD47, which is also known as the “don’t eat me” signal. This interaction mediates cell-cell adhesion and plays a role in the modulation of immune responses. The binding of SIRPγ to CD47 enhances antigen-specific T-cell proliferation and costimulates T-cell activation . The crystal structure of SIRPγ in complex with an antibody Fab fragment has been determined, revealing that the epitope for the Fab fragment is formed at the interface of the first and second domains of SIRPγ. This interaction stabilizes a conformation that favors SIRP dimer formation in the crystal structure .