Rab escort protein 1 also known as rab proteins geranylgeranyltransferase component A 1 is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that in humans is encoded by the CHM gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

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Function

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

Cysteine

Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...

 residues in their C-terminus to localize to the correct intracellular membrane.

Interactions

CHM (gene) has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with RAB1A

RAB1A

Ras-related protein Rab-1A is a protein that in humans is encoded by the RAB1A gene.-Interactions:RAB1A has been shown to interact with CHM, GOLGA5, CHML, RABAC1, MICAL1 and GOLGA2.-Further reading:...

, RAB7A

RAB7A

Ras-related protein Rab-7a is a protein that in humans is encoded by the RAB7A gene.Various mutations of RAB7A are associated with Hereditary sensory neuropathy type 1C , also known as Charcot-Marie-Tooth syndrome type 2B ....

 and RAB3A

RAB3A

Ras-related protein Rab-3A is a protein that in humans is encoded by the RAB3A gene.-Interactions:RAB3A has been shown to interact with CHM, RPH3A and RIMS1.-Further reading:...

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Clinical significance

Mutations in this gene are a cause of choroideremia

Choroideremia

Choroideremia is an X-linked recessive retinal degenerative disease that leads to the degeneration of the choriocapillaris, the retinal pigment epithelium, and the photoreceptor of the eye....

; also known as tapetochoroidal dystrophy (TCD). This X-linked disease is characterized by progressive dystrophy of the choroid, retinal pigment epithelium and retina.

Further reading

External links

• GeneReviews/NCBI/NIH/UW entry on Choroideremia