Satoh Akiko K, O'Tousa Joseph E, Ozaki Koichi, Ready Donald F
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
Development. 2005 Apr;132(7):1487-97. doi: 10.1242/dev.01704. Epub 2005 Feb 23.
In developing Drosophila photoreceptors, rhodopsin is trafficked to the rhabdomere, a specialized domain within the apical membrane surface. Rab11, a small GTPase implicated in membrane traffic, immunolocalizes to the trans-Golgi network, cytoplasmic vesicles and tubules, and the base of rhabdomeres. One hour after release from the endoplasmic reticulum, rhodopsin colocalizes with Rab11 in vesicles at the base of the rhabdomere. When Rab11 activity is reduced by three different genetic procedures, rhabdomere morphogenesis is inhibited and rhodopsin-bearing vesicles proliferate within the cytosol. Rab11 activity is also essential for development of MVB endosomal compartments; this is probably a secondary consequence of impaired rhabdomere development. Furthermore, Rab11 is required for transport of TRP, another rhabdomeric protein, and for development of specialized membrane structures within Garland cells. These results establish a role for Rab11 in the post-Golgi transport of rhodopsin and of other proteins to the rhabdomeric membranes of photoreceptors, and in analogous transport processes in other cells.
在发育中的果蝇光感受器中，视紫红质被运输到微绒毛，微绒毛是顶端膜表面内的一个特化区域。Rab11是一种参与膜运输的小GTP酶，免疫定位在反式高尔基体网络、细胞质囊泡和小管以及微绒毛基部。从内质网释放一小时后，视紫红质与Rab11在微绒毛基部的囊泡中共定位。当通过三种不同的遗传方法降低Rab11活性时，微绒毛形态发生受到抑制，并且含有视紫红质的囊泡在细胞质中增殖。Rab11活性对于多泡体（MVB）内体区室的发育也是必不可少的；这可能是微绒毛发育受损的次要后果。此外，Rab11是另一种微绒毛蛋白TRP运输所必需的，也是加兰细胞内特化膜结构发育所必需的。这些结果确立了Rab11在视紫红质和其他蛋白质从高尔基体后运输到光感受器的微绒毛膜以及在其他细胞中的类似运输过程中的作用。
