The outer and inner segments of vertebrate

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...

rod

photoreceptor cell A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiatio ...

s contain

phosducin Phosducin, also known as PDC, is a human protein and gene. It belongs to the phosducin family of proteins. This gene encodes a phosphoprotein, which is located in the outer and inner segments of the rod cells in the retina. This protein may part ...

, a soluble phosphoprotein that complexes with the beta/gamma-subunits of the

guanosine triphosphate Guanosine-5'-triphosphate (GTP) is a purine nucleoside triphosphate. It is one of the building blocks needed for the synthesis of RNA during the transcription process. Its structure is similar to that of the guanosine nucleoside, the only diffe ...

-binding protein,

transducin Transducin (Gt) is a protein naturally expressed in vertebrate retina rods and cones and it is very important in vertebrate phototransduction. It is a type of heterotrimeric G-protein with different α subunits in rod and cone photoreceptors. ...

. Light-induced changes in cyclic nucleotide levels modulate the

phosphorylation In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, wh ...

of phosducin by protein kinase A. The protein is thought to participate in the regulation of visual phototransduction or in the integration of photoreceptor metabolism. Similar proteins have been isolated from the

pineal gland The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep, sleep patterns in both circadian rhythm, circ ...

and it is believed that the function of the protein is the same in both retina and pineal gland.

Human proteins containing this domain

References

{{DEFAULTSORT:Phosducin Family Protein domains Protein families Peripheral membrane proteins