Rab6B

Rab6B is a member of the Rab family of small GTPases that regulate vesicular trafficking within the late secretory pathway. In humans, Rab6B is encoded by the RAB6B gene and serves as a paralog of Rab6A. Rab6 proteins function as molecular switches, cycling between an active GTP-bound state and an inactive GDP-bound state to control recruitment of effector proteins and coordinate steps of vesicle budding, transport, docking, and fusion.

The Rab6B protein localizes primarily to the Golgi apparatus and participates in intra-Golgi trafficking as well as Golgi-to-ER retrograde transport, contributing to the maintenance of Golgi organization and the efficiency of the secretory pathway. Like other Rab proteins, Rab6B activity is regulated by guanine nucleotide exchange factors (GEFs) that promote GTP loading and by GTPase-activating proteins (GAPs) that accelerate GTP hydrolysis.

Rab6B shares substantial sequence similarity with Rab6A, but the two paralogs differ in expression patterns and may have distinct cargo preferences or regulatory interactions. Rab6B is described as having a more restricted or tissue-specific expression pattern compared with Rab6A, though exact expression can vary by species and tissue and remains an area of ongoing study.

There are no widely established disease associations specific to Rab6B. As with other components of the Rab family, perturbations in Rab6B-regulated trafficking can affect the secretory pathway and cellular homeostasis, and Rab6B continues to be investigated to clarify its precise roles and interacting partners.