title: Immunocytochemical study of activin type IB receptor (XALK4) in Xenopus oocytes.
abstract: Studies have shown that the activin type IB receptor is specific for activin/nodal signaling. Activin is produced by follicle cells in the ovary, and is incorporated into the oocytes. Antisera against three peptides were prepared, encompassing the extracellular, intracellular and serine/threonine kinase domains of the Xenopus type IB activin receptor (XALK4). Immunocytochemistry was done using these antisera to investigate the distribution of XALK4 in the Xenopus ovary. All three antisera stained the mitochondrial cloud of Xenopus previtellogenic oocytes. Purified antibody against the intracellular domain also recognized the mitochondrial cloud. Immunoelectron microscopy localized XALK4 on the endoplasmic reticulum of the mitochondrial cloud, although not on mitochondria.
authors.affiliation: Department of Life Sciences (Biology), Japan Science and Technology Corporation, Tokyo University, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902.
authors.forename: Akimasa
authors.initials: A
authors.lastname: Fukui
authors.forename: Shinji
authors.initials: S
authors.lastname: Komazaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Miyoshi
authors.forename: Makoto
authors.initials: M
authors.lastname: Asashima
mesh_terms: D029404:Activin Receptors / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D030201:Activin Receptors, Type I; D030301:Activin Receptors, Type II / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D005260:Female; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology; D010053:Ovary / Q000166:cytology*; D010446:Peptide Fragments / Q000737:chemistry; D012313:RNA / Q000235:genetics; D014981:Xenopus / Q000235:genetics / Q000502:physiology*; D029867:Xenopus Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics
chemical_list: D010446:Peptide Fragments; D029867:Xenopus Proteins; D012313:RNA; D029404:Activin Receptors; D030201:Activin Receptors, Type I; D030301:Activin Receptors, Type II; C481805:acvr1b protein, Xenopus