Guanylyl cyclase-
activating protein 2
Activating Protein 2 (AP-2) is a family of closely related transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (geneti ...
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
human
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
s is encoded by the ''GUCA1B''
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 ...
.
Alternative names:
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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 ...
activator 1B
*
Retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
l
guanylyl cyclase activator
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
p24
Biological Role
Guanylyl cyclase-activating protein 2 is proposed to play a role in
dark adaptation.
Under
scotopic
In the study of visual perception, scotopic vision (or scotopia) is the vision of the eye under low-light conditions. The term comes from the Greek ''skotos'', meaning 'darkness', and ''-opia'', meaning 'a condition of sight'. In the human eye, co ...
conditions, calcium ions bind to three putative EF-hand calcium binding motifs which reduces the protein's ability to stimulate
guanylyl cyclase
Guanosine monophosphate (GMP), also known as 5′-guanidylic acid or guanylic acid ( conjugate base guanylate), is a nucleotide that is used as a monomer in RNA. It is an ester of phosphoric acid with the nucleoside guanosine. GMP consists of th ...
.
This contributes to the maintained responsiveness of rod photoreceptors through hyperpolarizing them during sustained darkness.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Retinitis Pigmentosa Overview
EF-hand-containing proteins
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