Rap2B regulation pathway
Activity of Rap-2B is mainly regulated by guanine nucleotide exchange factors (GEFs) that promote GTP-bound (active) state of Rap-2B. Main GEFs for Rap-2B are Rap guanine nucleotide exchange factors 2 and 5 ( PDZ-GEF1 and MR-GEF ) . Activated Adrenergic beta-1 receptor ( Beta-1 adrenergic receptor ) directly binds to PDZ-GEF1 and stimulates its GEF activity . MR-GEF is regulated by Muscle RAS oncogene homolog ( M-RAS ) that binds to and inhibits MR-GEF activity .