title: Characterization of Rab-interacting lysosomal protein in the brain of Bombyx mori.
abstract: Rab guanosine triphosphatases in eukaryotic cells are key regulators of membrane-trafficking events, such as exocytosis and endocytosis. Rab7 regulates traffic from early to late endosomes and from late endosomes to vacuoles/lysosomes. The Rab7-interacting lysosomal protein (RILP) was extracted from the silkworm, Bombyx mori (B. mori), and expressed in Escherichia coli (E. coli), followed by its purification. The glutathione sulfotransferase pull-down assay revealed that Rab7 of B. mori interacted with RILP of B. mori. We then produced antibodies against RILP of B. mori in rabbits for their use in Western immunoblotting and immunohistochemistry. Western immunoblotting of brain tissue for RILP revealed a single band, at approximately 50 kD. RILP-like immunohistochemical reactivity (RILP-ir) was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum. Furthermore, RILP-ir was colocalized with the eclosion hormone-ir and bombyxin-ir. However, RILP-ir was not colocalized with prothoracicotropic hormone-ir. These results were similar to those of Rab7 from our previous study. These findings suggest that RILP and Rab7 are involved in the neurosecretion in a restricted subtype of neurons in B. mori. Thus, our study is the first to report of a possible relationship between an insect Rab effector and neurosecretion.
authors.affiliation: Laboratory of Biological Chemistry, Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan, unotom@kobe-u.ac.jp.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Uno
authors.forename: Yuri
authors.initials: Y
authors.lastname: Isoyama
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Uno
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Kengo
authors.initials: K
authors.lastname: Kanamaru
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamagata
authors.forename: Michihiro
authors.initials: M
authors.lastname: Takagi
authors.forename: Akira
authors.initials: A
authors.lastname: Mizoguchi
authors.forename: Makio
authors.initials: M
authors.lastname: Takeda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D000818:Animals; D012831:Bombyx / Q000196:embryology* / Q000235:genetics; D054022:Cerebrum / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D007301:Insect Hormones; D007814:Larva; D008297:Male; D010053:Ovary / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D000090802:rab7 GTP-Binding Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D007301:Insect Hormones; D011506:Proteins; C018589:lysosomal proteins; D000090802:rab7 GTP-Binding Proteins; C009089:prothoracicotropic hormone; D020691:rab GTP-Binding Proteins