Ras-related protein Rap-1b (RAP1B) (RAP1B)

Ras-related protein Rap-1b (RAP1B) is a small GTPase belonging to the Ras superfamily that acts as a molecular switch to regulate various cellular processes, including cell adhesion, migration, and polarity [UniProt: P61224]. It is particularly well-characterized for its role in platelet activation, where it mediates integrin alpha-IIb/beta-3 signaling, making it a critical component of the hemostatic response [PubMed: 22535247]. In the context of oncology, RAP1B is often upregulated and promotes tumor progression by enhancing cell proliferation and metastatic potential in cancers such as squamous cell carcinoma and leukemia [PubMed: 30214034]. While RAP1B itself lacks highly specific direct small-molecule inhibitors, its activity can be modulated indirectly through the inhibition of geranylgeranyltransferase I, which is required for its membrane localization and functional activation [PubMed: 17297135]. Furthermore, targeting RAP1B mRNA using antisense oligonucleotides or siRNA is an emerging therapeutic strategy aimed at silencing its expression in malignant tissues [PubMed: 25605114]. Therapeutic intervention must be carefully managed, however, as systemic inhibition of RAP1B may lead to impaired platelet function and an increased risk of hemorrhage [PubMed: 22535247]. Beyond cancer and hematology, RAP1B is involved in vascular endothelial cell signaling and may play a role in inflammatory responses [PubMed: 21841143].

Other names

RAP1BKREV2Ras-related protein Krev-2GTP-binding protein smg p21B

Inhibition of post-translational geranylgeranylation to prevent membrane localization or degradation of mRNA via RNA interference to reduce protein synthesis.