RAP1B Gene: Function, Expression, and Clinical Significance

RAP1B is a small GTPase belonging to the RAS superfamily. It cycles between an active GTP-bound and inactive GDP-bound state, regulating diverse cellular processes including cell adhesion, migration, proliferation, and differentiation. RAP1B is widely expressed and plays critical roles in integrin-mediated adhesion, cadherin-based cell-cell junctions, and signal transduction pathways. Dysregulation of RAP1B has been implicated in cancer, cardiovascular diseases, and immune disorders.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Rap1 signaling pathway

• Integrin signaling pathway

• Cell adhesion molecules (CAMs)

• Chemokine signaling pathway

• Regulation of actin cytoskeleton

• MAPK signaling pathway

RAP1B is a 184-amino acid small GTPase (molecular weight ~21 kDa) that localizes to the plasma membrane and endomembranes. It shares high sequence similarity with RAP1A and other RAS family members. RAP1B is activated by guanine nucleotide exchange factors (GEFs) and inactivated by GTPase-activating proteins (GAPs). It regulates cell adhesion by promoting integrin activation and cadherin stabilization. RAP1B also modulates cell migration, proliferation, and differentiation through downstream effectors such as B-Raf, PI3K, and RalGDS. Post-translational modifications include prenylation and palmitoylation, which are essential for membrane targeting.