McGinnis J F, Stepanik P L, Chen W, Elias R, Cao W, Lerious V
Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City 73104, USA.
J Neurosci Res. 1999 Jan 15;55(2):252-60. doi: 10.1002/(SICI)1097-4547(19990115)55:2<252::AID-JNR13>3.0.CO;2-N.
Among retina-specific proteins, recoverin is unique with respect to its cellular regulation in that it is found in rods, cones, some bipolar cells, and a rare population of cells in the ganglion cell layer. Recoverin is a calcium-binding protein which inhibits rhodopsin kinase from phosphorylating rhodopsin. Because cells in the inner layers of the retina do not contain rhodopsin kinase, arrestin, or other phototransduction proteins, it seems likely that recoverin has a different function in those cell types. To study this protein more fully, antibodies were generated against the entire mouse recoverin protein, as well as against peptides from the amino and from the carboxyl termini. These antibodies confirmed the localization of recoverin in vivo and clearly demonstrated, in culture, cells which were recoverin positive and rhodopsin negative. Surprisingly, two unique cell phenotypes were seen in cell culture which are not found in vivo. These cells are [rhodopsin(+), recoverin(-)] and [arrestin(+), recoverin(-)]. These phenotypes appear to represent the same population of cells and suggest that the recoverin gene can be regulated independent of genes for other phototransduction proteins. This cell culture system will be useful for investigating environments and factors which participate in the expression of the recoverin gene, and may identify regulatory features of the recoverin gene which cause it to be illicitly expressed in small-cell lung carcinomas in cancer-associated retinopathy (CAR).
在视网膜特异性蛋白中，恢复蛋白在细胞调节方面独具特色，因为它存在于视杆细胞、视锥细胞、一些双极细胞以及神经节细胞层中罕见的细胞群体中。恢复蛋白是一种钙结合蛋白，可抑制视紫红质激酶对视紫红质进行磷酸化。由于视网膜内层的细胞不含视紫红质激酶、抑制蛋白或其他光转导蛋白，恢复蛋白在这些细胞类型中似乎具有不同的功能。为了更全面地研究这种蛋白，制备了针对整个小鼠恢复蛋白以及针对氨基末端和羧基末端肽段的抗体。这些抗体证实了恢复蛋白在体内的定位，并在培养中清楚地显示出恢复蛋白阳性但视紫红质阴性的细胞。令人惊讶的是，在细胞培养中观察到了两种独特的细胞表型，而在体内并未发现。这些细胞是[视紫红质(+)，恢复蛋白(-)]和[抑制蛋白(+)，恢复蛋白(-)]。这些表型似乎代表了同一细胞群体，表明恢复蛋白基因的调控可以独立于其他光转导蛋白的基因。这种细胞培养系统将有助于研究参与恢复蛋白基因表达的环境和因素，并可能识别出导致其在癌症相关性视网膜病变（CAR）的小细胞肺癌中异常表达的恢复蛋白基因的调控特征。
