RHEB Recombinant Protein

This gene is a member of the small GTPase superfamily and encodes a lipid-anchored, cell membrane protein with five repeats of the RAS-related GTP-binding region. This protein is vital in regulation of growth and cell cycle progression due to its role in the insulin/TOR/S6K signaling pathway. The protein has GTPase activity and shuttles between a GDP-bound form and a GTP-bound form, and farnesylation of the protein is required for this activity. Three pseudogenes have been mapped, two on chromosome 10 and one on chromosome 22. [provided by RefSeq, Jul 2008]

Function: Stimulates the phosphorylation of S6K1 and EIF4EBP1 through activation of mTORC1 signaling. Activates the protein kinase activity of mTORC1. Has low intrinsic GTPase activity. Ref.10 Ref.11 Ref.12 Ref.14 Ref.15 Ref.16

Enzyme regulation: Alternates between an inactive form bound to GDP and an active form bound to GTP. Inactivated by TSC1-TSC2 via the GTPase activating protein (GAP) domain of TSC2.

Subunit structure: Binds to mTORC1 in a guanyl nucleotide-independent manner. Interacts directly with MTOR, MLST8 and RPTOR. Interacts with TSC2. Ref.14 Ref.15

Subcellular location: Cell membrane; Lipid-anchor; Cytoplasmic side

Potential.

Tissue specificity: Ubiquitous. Highest levels observed in skeletal and cardiac muscle.

Post-translational modification: Farnesylation is important for efficiently activating mTORC1-mediated signaling.Phosphorylation by MAPKAPK5 impairs GTP-binding and inactivation

By similarity.

Miscellaneous: The conserved catalytic Gln-64 found in other Ras-like GTPases seems not to be involved in GTP hydrolysis in RHEB.

Sequence similarities: Belongs to the small GTPase superfamily. Rheb family.