title: Fast structural responses of gap junction membrane domains to AB5 toxins.
abstract: Gap junctions (GJs) represent connexin-rich membrane domains that connect interiors of adjoining cells in mammalian tissues. How fast GJs can respond to bacterial pathogens has not been known previously. Using Bessel beam plane illumination and confocal spinning disk microscopy, we found fast (~500 ms) formation of connexin-depleted regions (CDRs) inside GJ plaques between cells exposed to AB5 toxins. CDR formation appears as a fast redistribution of connexin channels within GJ plaques with minor changes in outline or geometry. CDR formation does not depend on membrane trafficking or submembrane cytoskeleton and has no effect on GJ conductance. However, CDR responses depend on membrane lipids, can be modified by cholesterol-clustering agents and extracellular K(+) ion concentration, and influence cAMP signaling. The CDR response of GJ plaques to bacterial toxins is a phenomenon observed for all tested connexin isoforms. Through signaling, the CDR response may enable cells to sense exposure to AB5 toxins. CDR formation may reflect lipid-phase separation events in the biological membrane of the GJ plaque, leading to increased connexin packing and lipid reorganization. Our data demonstrate very fast dynamics (in the millisecond-to-second range) within GJ plaques, which previously were considered to be relatively stable, long-lived structures.
authors.affiliation: Institute of Biology, Center for Structural and Cell Biology in Medicine, University of Lübeck, 23562 Lübeck, Germany.
authors.forename: Irina V
authors.initials: IV
authors.lastname: Majoul
authors.forename: Liang
authors.initials: L
authors.lastname: Gao
authors.forename: Eric
authors.initials: E
authors.lastname: Betzig
authors.forename: Daria
authors.initials: D
authors.lastname: Onichtchouk
authors.forename: Eugenia
authors.initials: E
authors.lastname: Butkevich
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kozlov
authors.forename: Feliksas
authors.initials: F
authors.lastname: Bukauskas
authors.forename: Michael V L
authors.initials: MV
authors.lastname: Bennett
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lippincott-Schwartz
authors.forename: Rainer
authors.initials: R
authors.lastname: Duden
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002522:Chlorocebus aethiops; D017630:Connexins / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005372:Filipin; D005453:Fluorescence; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D007091:Image Processing, Computer-Assisted; D008563:Membrane Lipids / Q000378:metabolism*; D018613:Microscopy, Confocal / Q000379:methods; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D053778:Thiazolidines; D014709:Vero Cells
chemical_list: D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D017630:Connexins; D017931:DNA Primers; D008563:Membrane Lipids; D053778:Thiazolidines; D005372:Filipin; D000242:Cyclic AMP; D011188:Potassium; C037067:latrunculin A
keywords: cell–cell junctions; cholesterol; connexin actin; membrane traffic