Figure 2. MRCK/gek regulates apical Myosin activation and morphogenesis in differentiating Drosophila photoreceptors.

(a) Scheme illustrating the similarities and corresponding plasma membrane domains of vertebrate epithelial cells and Drosophila photoreceptors. Indicated are apical microvilli and the apical zone enriched in active Myosin-II. (b-d) Confocal sections of Drosophila pupal mosaic retinas showing wild type cells (blue nuclei) and cells mutant for gek were stained for F-actin (c) or p-MLC (b). Mutant cells are labelled with asterisks. Quantification of apical actin enrichment shows analysis of wild type and mutant cells (paired within sections; n represents 11 animals, a t-test was used to calculate the p value). (e,f) Analysis of rhabdomere integrity in wild type and gek mutant cells using 2 different gek alleles (gek^NP5192 or gek¹⁰⁸⁰) demonstrates severe defects including splitting. (g,h) Confocal sections of Drosophila eyes showing wild type cells and cells mutant for gek^NP5192 but expressing sqh-Sqh^EE (blue nuclei; labelled with asterisks; the quantification represents pairs within sections and is based on n = 8 animals, a t-test was used to calculate the p value).