title: The claudin Megatrachea protein complex.
abstract: Claudins are integral transmembrane components of the tight junctions forming trans-epithelial barriers in many organs, such as the nervous system, lung, and epidermis. In Drosophila three claudins have been identified that are required for forming the tight junctions analogous structure, the septate junctions (SJs). The lack of claudins results in a disruption of SJ integrity leading to a breakdown of the trans-epithelial barrier and to disturbed epithelial morphogenesis. However, little is known about claudin partners for transport mechanisms and membrane organization. Here we present a comprehensive analysis of the claudin proteome in Drosophila by combining biochemical and physiological approaches. Using specific antibodies against the claudin Megatrachea for immunoprecipitation and mass spectrometry, we identified 142 proteins associated with Megatrachea in embryos. The Megatrachea interacting proteins were analyzed in vivo by tissue-specific knockdown of the corresponding genes using RNA interference. We identified known and novel putative SJ components, such as the gene product of CG3921. Furthermore, our data suggest that the control of secretion processes specific to SJs and dependent on Sec61p may involve Megatrachea interaction with Sec61 subunits. Also, our findings suggest that clathrin-coated vesicles may regulate Megatrachea turnover at the plasma membrane similar to human claudins. As claudins are conserved both in structure and function, our findings offer novel candidate proteins involved in the claudin interactome of vertebrates and invertebrates.
authors.affiliation: Research Group Molecular Organogenesis, Max Planck Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen, Germany.
authors.forename: Martin H J
authors.initials: MH
authors.lastname: Jaspers
authors.forename: Kai
authors.initials: K
authors.lastname: Nolde
authors.forename: Matthias
authors.initials: M
authors.lastname: Behr
authors.forename: Seol-hee
authors.initials: SH
authors.lastname: Joo
authors.forename: Uwe
authors.initials: U
authors.lastname: Plessmann
authors.forename: Miroslav
authors.initials: M
authors.lastname: Nikolov
authors.forename: Henning
authors.initials: H
authors.lastname: Urlaub
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schuh
mesh_terms: D000818:Animals; D057167:Claudins / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D055785:Gene Knockdown Techniques; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D010641:Phenotype; D025941:Protein Interaction Mapping; D021381:Protein Transport; D020543:Proteome / Q000378:metabolism; D034622:RNA Interference; D012137:Respiratory System / Q000196:embryology / Q000378:metabolism; D055571:Secretory Pathway; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D057167:Claudins; D029721:Drosophila Proteins; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D020543:Proteome; C577157:pck protein, Drosophila