RHEB2

RHEB2, or Ras homolog enriched in brain 2, is a small GTPase of the Ras superfamily described as a paralog of RHEB and identified in several vertebrate genomes. As a member of the RHEB family, RHEB2 is predicted to function as a molecular switch that cycles between active GTP-bound and inactive GDP-bound states, translating regulatory signals into cellular responses.

In studies of RHEB proteins, RHEB is known to activate mTORC1 signaling by directly interacting with components of the TOR complex. RHEB2 is similarly suggested to participate in mTOR pathway regulation, but the extent and specifics of its involvement appear to be context- and species-dependent, with functional data being more limited than for RHEB.

Expression and regulation: Across species, RHEB2 expression patterns vary and are generally less well characterized than those of RHEB. Regulatory inputs may include nutrient availability, energy status, and growth cues that modulate mTOR activity.

Evolution and nomenclature: RHEB2 is one of several RHEB-like GTPases. Phylogenetic analyses typically place RHEB2 in close relation to RHEB, reflecting their common ancestry in the Ras superfamily.

Clinical and research relevance: Because direct, consistent functional data for RHEB2 are limited, there are no well-established disease associations specific to RHEB2. Ongoing studies aim to clarify its biological roles and potential contribution to diseases involving mTOR signaling.

See also: RHEB; mTOR signaling; Ras-related small GTPases.