Osmotic swelling activates a novel anionic current with VRAC-like properties in a cytoplasmic droplet membrane from Phycomyces blakesleeanus sporangiophores

Strahinja Križak; Ljiljana Nikolić; Marina Stanić; Milan Žižić; Joanna Zakrzewska; Miroslav Živić; Nataša Todorović

doi:10.1016/j.resmic.2015.02.004

Osmotic swelling activates a novel anionic current with VRAC-like properties in a cytoplasmic droplet membrane from Phycomyces blakesleeanus sporangiophores

Res Microbiol. 2015 Apr;166(3):162-73. doi: 10.1016/j.resmic.2015.02.004. Epub 2015 Feb 18.

Authors

Strahinja Križak¹, Ljiljana Nikolić², Marina Stanić³, Milan Žižić⁴, Joanna Zakrzewska⁵, Miroslav Živić⁶, Nataša Todorović⁷

Affiliations

¹ Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia. Electronic address: strahinjakrizak@imsi.bg.ac.rs.
² Department of Neurophysiology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Bulevar Despota Stefana 142, 11000 Belgrade, Serbia. Electronic address: ljnikolic@ibiss.bg.ac.rs.
³ Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia. Electronic address: mstanic@imsi.rs.
⁴ Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia. Electronic address: mzizic@imsi.rs.
⁵ NMR Laboratory, Institute of General and Physical Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia. Electronic address: jzakrzewska@iofh.bg.ac.rs.
⁶ Institute of Physiology and Biochemistry, University of Belgrade -Faculty of Biology, Studentski trg 16, 11000 Belgrade, Serbia. Electronic address: mzivic@bio.bg.ac.rs.
⁷ Department of Neurophysiology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Bulevar Despota Stefana 142, 11000 Belgrade, Serbia. Electronic address: nara@ibiss.bg.ac.rs.

PMID: 25701762
DOI: 10.1016/j.resmic.2015.02.004

Abstract

We describe here whole-cell currents of droplets prepared from the apical region of growing Phycomyces blakesleeanus sporangiophores. Whole-cell current recordings revealed the osmotically activated, outwardly rectifying, fast inactivating instantaneous current (ORIC) with biophysical properties closely resembling volume-regulated anionic current (VRAC). ORIC is activated under conditions of osmotically induced swelling and shows strong selectivity for anions over cations. In addition, ORIC shows voltage and time-dependent inactivation at positive potentials and recovery from inactivation at negative potentials. ORIC is blocked by anthracene-9-carboxylic acid, an anion channel blocker, in a voltage-dependent manner. This is the first report of the presence of VRAC-like current in an organism outside the chordate lineage.

Keywords: A-9-C; Filamentous fungi; Outward rectifier; Voltage-dependent inactivation; Whole-cell patch-clamp.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anthracenes / pharmacology
Cell Membrane / physiology*
Ion Channel Gating
Ion Channels / physiology*
Membrane Potentials*
Osmotic Pressure*
Patch-Clamp Techniques
Phycomyces / physiology*

Substances

Anthracenes
Ion Channels
9-anthroic acid