Drosophila Crumbs is a positional cue in photoreceptor adherens junctions and rhabdomeres

• Published in: Nature (London) 2002-03, Vol.416 (6877), p.178-183
• Main Authors: Choi, Kwang-Wook, Izaddoost, Shayan, Nam, Sang-Chul, Bhat, Manzoor A, Bellen, Hugo J
• Format: Article
• Language: English
• Subjects: Adherens Junctions - chemistry; Adherens Junctions - metabolism; Adherens Junctions - ultrastructure; Amino Acid Sequence; Animals; Binding Sites; Biochemistry. Physiology. Immunology; Biological and medical sciences; Cell Membrane - metabolism; Cell Polarity; Conserved Sequence; CRB1 protein; Crumbs protein; Cues; Drosophila; Drosophila melanogaster - cytology; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila melanogaster - ultrastructure; Drosophila Proteins - chemistry; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Embryos; Eye - cytology; Eye - embryology; Eye - metabolism; Eye - ultrastructure; Eye Proteins; Eyes & eyesight; Fundamental and applied biological sciences. Psychology; Humanities and Social Sciences; Humans; Insect Proteins - metabolism; Insecta; Insects; Invertebrates; Leber congenital amaurosis; letter; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Molecular Sequence Data; Morphogenesis; multidisciplinary; Mutation; Mutation - genetics; Nerve Tissue Proteins; Phenotype; Photoreceptor Cells, Invertebrate - cytology; Photoreceptor Cells, Invertebrate - embryology; Photoreceptor Cells, Invertebrate - metabolism; Photoreceptor Cells, Invertebrate - ultrastructure; Physiology. Development; Protein Structure, Tertiary; Proteins; rhabdomeres; Science; Science (multidisciplinary); Sequence Alignment; Space life sciences
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature720

Drosophila Crumbs (Crb) is required for apical-basal polarity and is an apical determinant in embryonic epithelia. Here, we describe properties of Crb that control the position and integrity of the photoreceptor adherens junction and photosensitive organ, or rhabdomere. In contrast to normal photoreceptor adherens junctions and rhabdomeres, which span the depth of the retina, adherens junctions and rhabdomeres of Crb-deficient photoreceptors initially accumulate at the top of the retina and fail to maintain their integrity as they stretch to the retinal floor. We show that Crb controls localization of the adherens junction through its intracellular domain containing a putative binding site for a protein 4.1 superfamily protein (FERM). Although loss of Crb or overexpression of the FERM binding domain causes mislocalization of adherens junctions, they do not result in a significant loss of photoreceptor polarity. Mutations in CRB1, a human homologue of crb, are associated with photoreceptor degeneration in retinitis pigmentosa 12 (RP12) and Leber congenital amaurosis (LCA). The intracellular domain of CRB1 behaves similarly to its Drosophila counterpart when overexpressed in the fly eye. Our studies may provide clues for mechanisms of photoreceptor degeneration in RP12 and LCA.