| First Author | Lee A | Year | 2007 |
| Journal | J Neurosci | Volume | 27 |
| Issue | 46 | Pages | 12743-54 |
| PubMed ID | 18003854 | Mgi Jnum | J:141561 |
| Mgi Id | MGI:3818796 | Doi | 10.1523/JNEUROSCI.4264-07.2007 |
| Citation | Lee A, et al. (2007) Phosphorylation of the Ca2+-binding protein CaBP4 by protein kinase C zeta in photoreceptors. J Neurosci 27(46):12743-54 |
| abstractText | CaBP4 is a calmodulin-like neuronal calcium-binding protein that is crucial for the development and/or maintenance of the cone and rod photoreceptor synapse. Previously, we showed that CaBP4 directly regulates Ca(v)1 L-type Ca2+ channels, which are essential for normal photoreceptor synaptic transmission. Here, we show that the function of CaBP4 is regulated by phosphorylation. CaBP4 is phosphorylated by protein kinase C zeta (PKCzeta) at serine 37 both in vitro and in the retina and colocalizes with PKCzeta in photoreceptors. CaBP4 phosphorylation is greater in light-adapted than dark-adapted mouse retinas. In electrophysiological recordings of cells transfected with Ca(v)1.3 and CaBP4, mutation of the serine 37 to alanine abolished the effect of CaBP4 in prolonging the Ca2+ current through Ca(v)1.3 channel, whereas inactivating mutations in the CaBP4 Ca2+-binding sites strengthened Ca(v)1.3 modulation. These findings demonstrate how light-stimulated changes in CaBP4 phosphorylation and Ca2+ binding may regulate presynaptic Ca2+ signals in photoreceptors. |
