Calcium-binding proteins: intracellular sensors from the calmodulin superfamily.
In all eukaryotic cells, and particularly in neurons, Ca(2+) ions are important second messengers in a variety of cellular signaling pathways. In the retina, Ca(2+) modulation plays a crucial function in the development of the visual system's neuronal connectivity and a regulatory role in the conversion of the light signal received by photoreceptors into an electrical signal transmitted to the brain. Therefore, the study of retinal Ca(2+)-binding proteins, which frequently mediate Ca(2+) signaling, has given rise to the important discovery of two subfamilies of these proteins, neuronal Ca(2+)-binding proteins (NCBPs) and calcium-binding proteins (CaBPs), that display similarities to calmodulin (CaM). These and other Ca(2+)-binding proteins are integral components of cellular events controlled by Ca(2+). Some members of these subfamilies also play a vital role in signal transduction outside of the retina. The expansion of the CaM-like protein family reveals diversification among Ca(2+)-binding proteins that evolved on the basis of the classic molecule, CaM. A large number of NCBP and CaBP subfamily members would benefit from their potentially specialized role in Ca(2+)-dependent cellular processes. Pinpointing the role of these proteins will be a challenging task for further research.
Haeseleer
Françoise
F
Department of Ophthalmology, University of Washington, Seattle, Washington 98195, USA.
Imanishi
Yoshikazu
Y
Sokal
Izabela
I
Filipek
Slawomir
S
Palczewski
Krzysztof
K
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000145:classification / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D020832:EF Hand Motifs / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012160:Retina / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology
D002135:Calcium-Binding Proteins; D002147:Calmodulin