Rod cGMP-specific 3',5'-cyclic phosphodiesterase subunit alpha is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''PDE6A''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
PDE6A encodes the cyclic-GMP (
cGMP CGMP is an initialism. It can refer to:
*cyclic guanosine monophosphate (cGMP)
* current good manufacturing practice (cGMP)
*CGMP, Cisco Group Management Protocol, the Cisco version of Internet Group Management Protocol
The Internet Group Manag ...
) specific
phosphodiesterase
A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, ''phosphodiesterase'' refers to cyclic nucleotide phosphodiesterases, which have great clinical significance and are described below. However, there are many oth ...
6A alpha subunit, expressed in cells of the retinal rod outer segment. The phosphodiesterase 6
holoenzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
is a
heterotrimer
thumbnail, 400px, Trimeric form of a TNF-α mutant
In biochemistry, a protein trimer is a macromolecular complex formed by three, usually non-covalently bound, macromolecules like proteins or nucleic acids. A protein trimer often occurs from the ...
composed of an alpha, beta, and two gamma subunits. cGMP is an important regulator of
rod cell
Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in ...
membrane current, and its dynamic concentration is established by phosphodiesterase 6A cGMP hydrolysis and
guanylate cyclase
Guanylate cyclase (EC 4.6.1.2, also known as guanyl cyclase, guanylyl cyclase, or GC; systematic name GTP diphosphate-lyase (cyclizing; 3′,5′-cyclic-GMP-forming)) is a lyase enzyme that converts guanosine triphosphate (GTP) to cyclic guanosi ...
cGMP synthesis.
Mutations
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosi ...
in PDE6A have been identified as one cause of autosomal recessive
retinitis pigmentosa
Retinitis pigmentosa (RP) is a member of a group of genetic disorders called inherited retinal dystrophy (IRD) that cause loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision (side and upper or lower visua ...
.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Retinitis Pigmentosa Overview
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