title: Bves modulates tight junction associated signaling.
abstract: Blood vessel epicardial substance (Bves) is a transmembrane adhesion protein that regulates tight junction (TJ) formation in a variety of epithelia. The role of TJs within epithelium extends beyond the mechanical properties. They have been shown to play a direct role in regulation of RhoA and ZONAB/DbpA, a y-box transcription factor. We hypothesize that Bves can modulate RhoA activation and ZONAB/DbpA activity through its regulatory effect on TJ formation. Immortalized human corneal epithelial (HCE) cells were stably transfected with Flag-tagged full length chicken Bves (w-Bves) or C-terminus truncated Bves (t-Bves). We found that stably transfected w-Bves and t-Bves were interacting with endogenous human Bves. However, interaction with t-Bves appeared to disrupt cell membrane localization of endogenous Bves and interaction with ZO-1. w-Bves cells exhibited increased TJ function reflected by increased trans-epithelial electrical resistance, while t-Bves cells lost TJ protein immunolocalization at cell-cell contacts and exhibited decreased trans-epithelial electrical resistance. In parental HCE and w-Bves cells ZONAB/DbpA and GEF-H1 were seen at cell borders in the same pattern as ZO-1. However, expression of t-Bves led to decreased membrane localization of both ZONAB/DbpA and GEF-H1. t-Bves cells had increased RhoA activity, as indicated by a significant 30% increase in FRET activity compared to parental HCE cells. ZONAB/DbpA transcriptional activity, assessed using a luciferase reporter probe, was increased in t-Bves cells. These studies demonstrate that Bves expression and localization can regulate RhoA and ZONAB/DbpA activity.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America. patricia.k.russ@vanderbilt.edu
authors.forename: Patricia K
authors.initials: PK
authors.lastname: Russ
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Pino
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Williams
authors.forename: David M
authors.initials: DM
authors.lastname: Bader
authors.forename: Frederick R
authors.initials: FR
authors.lastname: Haselton
authors.forename: Min S
authors.initials: MS
authors.lastname: Chang
mesh_terms: D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D015815:Cell Adhesion Molecules; D002460:Cell Line; D004847:Epithelial Cells; D019573:Epithelium, Corneal / Q000166:cytology; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D009124:Muscle Proteins; D015398:Signal Transduction; D019108:Tight Junctions / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D015815:Cell Adhesion Molecules; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D020742:rhoA GTP-Binding Protein; C530749:POPDC1 protein, human; C094867:YBX3 protein, human