CHM
Function
Substrate-binding subunit of the Rab geranylgeranyltransferase (GGTase) complex. Binds unprenylated Rab proteins and presents the substrate peptide to the catalytic component B composed of RABGGTA and RABGGTB, and remains bound to it after the geranylgeranyl transfer reaction. The component A is thought to be regenerated by transferring its prenylated Rab back to the donor membrane. Besides, a pre-formed complex consisting of CHM and the Rab GGTase dimer (RGGT or component B) can bind to and prenylate Rab proteins; this alternative pathway is proposed to be the predominant pathway for Rab protein geranylgeranylation.
Involvement in disease
Choroideremia
CHM
An X-linked recessive disease characterized by a slowly progressive degeneration of the choroid, photoreceptors, and retinal pigment epithelium. Affected males develop night blindness in their teenage years followed by loss of peripheral vision and complete blindness at middle age. Carrier females are generally asymptomatic but funduscopic examination often shows patchy areas of chorioretinal atrophy.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the Rab GDI family.
Cellular localization
- Cytoplasm
- Cytosol
Alternative names
REP1, TCD, CHM, Rab proteins geranylgeranyltransferase component A 1, Choroideremia protein, Rab escort protein 1, TCD protein, REP-1