Rab escort protein

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Choroideremia (Rab escort protein 1)
Symbols CHM ; DXS540; GGTA; HSD-32; REP-1; TCD
External IDs OMIM300390 MGI892979 HomoloGene334 GeneCards: CHM Gene
RNA expression pattern
PBB GE CHM 207099 s at tn.png
More reference expression data
Species Human Mouse
Entrez 1121 12662
Ensembl ENSG00000188419 ENSMUSG00000025531
UniProt P24386 A2AD03
RefSeq (mRNA) NM_000390 NM_018818
RefSeq (protein) NP_000381 NP_061288
Location (UCSC) Chr X:
85.86 – 86.05 Mb
Chr X:
113.04 – 113.19 Mb
PubMed search [1] [2]

Rab escort protein 1 also known as rab proteins geranylgeranyltransferase component A 1 is an enzyme that in humans is encoded by the CHM gene.[1][2]


This gene encodes component A of the RAB geranylgeranyl transferase holoenzyme. In the dimeric holoenzyme, this subunit binds unprenylated Rab GTPases and then presents them to the catalytic Rab GGTase subunit for the geranylgeranyl transfer reaction. Rab GTPases need to be geranylgeranyled on either one or two cysteine residues in their C-terminus to localize to the correct intracellular membrane.[2]


CHM (gene) has been shown to interact with RAB1A,[3] RAB7A[4][5] and RAB3A.[3][6]

Clinical significance[edit]

Mutations in this gene are a cause of choroideremia; also known as tapetochoroidal dystrophy (TCD). This X-linked disease is characterized by progressive dystrophy of the choroid, retinal pigment epithelium and retina.[2]

See also[edit]


  1. ^ Molloy CM, van de Pol TJ, Brohet RM, Ropers HH, Cremers FP (May 1992). "Three RFLPs for pZ11 (DXS540) in the choroideremia gene at Xq21.2". Nucleic Acids Res 20 (6): 1434. doi:10.1093/nar/20.6.1434. PMC 312214. PMID 1373238. 
  2. ^ a b c "Entrez Gene: CHM choroideremia (Rab escort protein 1)". 
  3. ^ a b Cremers FP, Armstrong SA, Seabra MC, Brown MS, Goldstein JL (Jan 1994). "REP-2, a Rab escort protein encoded by the choroideremia-like gene". J. Biol. Chem. 269 (3): 2111–7. PMID 8294464. 
  4. ^ Rak A, Pylypenko O, Niculae A, Goody RS, Alexandrov K (Jan 2003). "Crystallization and preliminary X-ray diffraction analysis of monoprenylated Rab7 GTPase in complex with Rab escort protein 1". J. Struct. Biol. 141 (1): 93–5. doi:10.1016/S1047-8477(02)00634-2. PMID 12576024. 
  5. ^ Alexandrov K, Simon I, Iakovenko A, Holz B, Goody RS, Scheidig AJ (Apr 1998). "Moderate discrimination of REP-1 between Rab7 x GDP and Rab7 x GTP arises from a difference of an order of magnitude in dissociation rates". FEBS Lett. 425 (3): 460–4. doi:10.1016/S0014-5793(98)00290-7. PMID 9563513. 
  6. ^ Pereira-Leal JB, Strom M, Godfrey RF, Seabra MC (Jan 2003). "Structural determinants of Rab and Rab Escort Protein interaction: Rab family motifs define a conserved binding surface". Biochem. Biophys. Res. Commun. 301 (1): 92–7. doi:10.1016/S0006-291X(02)02963-7. PMID 12535645. 

Further reading[edit]

External links[edit]