Signal Regulatory Protein Gamma (SIRPγ)

Signal regulatory protein gamma (SIRPγ) is a member of the SIRP family of receptor-type transmembrane glycoproteins. SIRPγ is uniquely expressed on human T-cells and binds to CD47 on antigen-presenting cells, mediating cell-cell adhesion. It functions as a checkpoint regulator for human effector T-cells; reduced expression can potentiate effector responses. Genetic variants and altered expression have been associated with autoimmune diseases like type 1 diabetes, multiple sclerosis, and systemic lupus erythematosus. While structurally similar to other SIRP family members, its short cytoplasmic tail means it does not directly transmit intracellular signals.

Modulates intercellular interactions; considered "nonsignaling" due to the lack of classical signaling motifs.