title: Characterization of the column and autocellular junctions that define the vasculature of gill lamellae.
abstract: Novel adhesion junctions have been characterized that are formed at the interface between pillar cells and collagen columns, both of which are essential constituents of the gill lamellae in fish. We termed these junctions the "column junction" and "autocellular junction" and determined their molecular compositions by immunofluorescence microscopy using pufferfish. We visualized collagen columns by concanavalin A staining and found that the components of integrin-mediated cell-matrix adhesion, such as talin, vinculin, paxillin, and fibronectin, were concentrated on plasma membranes surrounding collagen columns (column membranes). This connection is analogous to the focal adhesion of cultured mammalian cells, dense plaque of smooth muscle cells, and myotendinous junction of skeletal muscle cells. We named this connection the "column junction." In the cytoplasm near the column, actin fibers, actinin, and a phosphorylated myosin light chain of 20 kDa are densely located, suggesting the contractile nature of pillar cells. The membrane infoldings surrounding the collagen columns were found to be connected by the autocellular junction, whose components are highly tyrosine-phosphorylated and contain the tight junction protein ZO-1. This study represents the first molecular characterization and fluorescence visualization of the column and autocellular junctions involved in both maintaining structural integrity and the hemodynamics of the branchial lamellae.
authors.affiliation: Department of Biological Sciences, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kato
authors.forename: Korefumi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Kudo
authors.forename: Yen Ha
authors.initials: YH
authors.lastname: Tran
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Hirose
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism; D021982:Cell-Matrix Junctions; D042783:Endothelial Cells / Q000378:metabolism / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism / Q000648:ultrastructure; D024022:Fibrillar Collagens / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005880:Gills / Q000098:blood supply* / Q000166:cytology* / Q000648:ultrastructure; D007797:Laminin / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D032389:Myocytes, Smooth Muscle / Q000000981:diagnostic imaging / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D023721:Tetraodontiformes / Q000033:anatomy & histology*; D019108:Tight Junctions / Q000378:metabolism; D014463:Ultrasonography; D062826:Zonula Occludens-1 Protein
chemical_list: D024022:Fibrillar Collagens; D007797:Laminin; D008565:Membrane Proteins; D010750:Phosphoproteins; D062826:Zonula Occludens-1 Protein