SHB

SHb most commonly refers to the SH2 domain-containing adaptor protein B, a cytoplasmic signaling adaptor in humans. The protein is encoded by the SHB gene. It functions as an intracellular docking protein that lacks catalytic activity but contains an SH2 domain that binds phosphotyrosine motifs, enabling it to link activated receptors and other signaling proteins to downstream pathways. SHB participates in signaling downstream of several receptor tyrosine kinases, including VEGF receptors, FGFRs, PDGFRs, and insulin receptors, and it is involved in integrin-mediated signaling at focal adhesions. Through interactions with proteins such as FAK and Crk, SHB helps assemble signaling complexes that regulate cell migration, proliferation, and survival. SHB is broadly expressed, with higher levels in endothelial and hematopoietic cells, and localizes to the cytoplasm and focal adhesion sites, though some isoforms can affect subcellular distribution.

Clinical and genetic context: Variants or altered expression of SHB have been studied in relation to metabolic disorders, autoimmune diseases, and cancer risk, but results are not conclusive.

In other contexts, SHb may appear in literature with different meanings depending on the field. When encountered, context should be used to determine the intended interpretation.