Caldendrins in the inner retina.
Caldendrin is the first member of a novel family of Ca2+-binding proteins (CaBPs). Its unique two-domain structure is composed of a calmodulin-homologous teminus and an unrelated N-terminal part. The latter is thought to mediate the tight association of caldendrin with the subsynaptic cytoskeleton. Caldendrin is expressed in forebrain regions with a laminar cytoarchitecture as well as in the inner retina where it is localized to OFF cone bipolar and a subset of amacrine and ganlion cells. In addition, caldendrin is prominently present in processes and synapses of the inner plexiform layer. Thus, caldendrin-immunoreactivity is displayed by ubpopulations of most retinal cell classes, with the exception of glial cells. Caldendrin is most likely involved in dendritic Ca2+-signaling, one of the functions of its close relative, calmodulin. However, several lines of evidence suggest that due to its unique properties caldendrin might not merely substitute for calmodulin. t is speculated that either the specific enrichment in cellular micro-compartments like the postsynaptic cytomatrix, the unique two-domain structure or the altered distribution of surface charges renders caldendrin specific for distinct binding partners or certain Ca2+-triggered signaling events.
Seidenbecher
Constanze I
CI
AG Molecular of Plasicity, Department of Neurochemistry/Molecular Biology, Leibnitz Institute for Neurobiology, 39118 Magdeburg, Germany. seidenc@ifn-magdeburg.de
Reissner
C
C
Kreutz
Michael R
MR
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism / Q000502:physiology*; D016548:Prosencephalon / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D012160:Retina / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D002135:Calcium-Binding Proteins; D009419:Nerve Tissue Proteins; C085577:Ca2+-binding protein-1; D002118:Calcium