Shark, a Src homology 2, ankyrin repeat, tyrosine kinase, is expressed on the apical surfaces of ectodermal epithelia.
Tyrosine kinases, ankyrin repeats, and Src homology 2 domains play central roles in developmental processes. The cloning of a cDNA for Shark, a single protein that possesses all three domains, is described. During Drosophila embryogenesis, Shark is expressed exclusively by ectodermally derived epithelia and is localized preferentially to the apical surface of these cells. This apical localization persists, even as tissues undergo complex invaginations, moving from the external surface of embryos to form internal structures, but expression is lost when cells lose their polarity. This pattern closely mimics the expression of Crumbs, a protein necessary for proper organization of ectodermal epithelia. Shark's structure and localization pattern suggest that it functions in a signaling pathway for epithelial cell polarity, possibly transducing the Crumbs signal.
Ferrante
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AW
Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461.
Reinke
R
R
Stanley
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ER
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology*; D004475:Ectoderm / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000201:enzymology / Q000502:physiology; D004848:Epithelium / Q000201:enzymology; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis*; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D029721:Drosophila Proteins; C092552:Shark protein, Drosophila; D011505:Protein-Tyrosine Kinases