Identification and characterization of the three members of the CLC family of anion transport proteins in Trypanosoma brucei

Michael E Steinmann; Remo S Schmidt; Juan P Macêdo; Christina Kunz Renggli; Peter Bütikofer; Doris Rentsch; Pascal Mäser; Erwin Sigel

doi:10.1371/journal.pone.0188219

Identification and characterization of the three members of the CLC family of anion transport proteins in Trypanosoma brucei

PLoS One. 2017 Dec 15;12(12):e0188219. doi: 10.1371/journal.pone.0188219. eCollection 2017.

Authors

Michael E Steinmann¹, Remo S Schmidt^{2

3}, Juan P Macêdo⁴, Christina Kunz Renggli^{2

3}, Peter Bütikofer¹, Doris Rentsch⁴, Pascal Mäser^{2

3}, Erwin Sigel¹

Affiliations

¹ Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
² Swiss Tropical and Public Health Institute, Basel, Switzerland.
³ University of Basel, Basel, Switzerland.
⁴ Institute of Plant Sciences, University of Bern, Bern, Switzerland.

Abstract

CLC type anion transport proteins are homo-dimeric or hetero-dimeric with an integrated transport function in each subunit. We have identified and partially characterized three members of this family named TbVCL1, TbVCL2 and TbVCL3 in Trypanosoma brucei. Among the human CLC family members, the T. brucei proteins display highest similarity to CLC-6 and CLC-7. TbVCL1, but not TbVCL2 and TbVCL3 is able to complement growth of a CLC-deficient Saccharomyces cerevisiae mutant. All TbVCL-HA fusion proteins localize intracellulary in procyclic form trypanosomes. TbVCL1 localizes close to the Golgi apparatus and TbVCL2 and TbVCL3 to the endoplasmic reticulum. Upon expression in Xenopus oocytes, all three proteins induce similar outward rectifying chloride ion currents. Currents are sensitive to low concentrations of DIDS, insensitive to the pH in the range 5.4 to 8.4 and larger in nitrate than in chloride medium.

MeSH terms

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
Animals
Chloride Channels / antagonists & inhibitors
Chloride Channels / genetics*
Chloride Channels / metabolism
Chlorides / metabolism
Endoplasmic Reticulum / metabolism*
Endoplasmic Reticulum / ultrastructure
Female
Gene Expression
Genetic Complementation Test
Golgi Apparatus / metabolism
Golgi Apparatus / ultrastructure
Humans
Ion Transport
Life Cycle Stages / physiology*
Membrane Potentials / drug effects
Membrane Potentials / physiology
Nitrates / metabolism
Oocytes / cytology
Oocytes / drug effects
Oocytes / metabolism
Patch-Clamp Techniques
Protein Multimerization
Protozoan Proteins / antagonists & inhibitors
Protozoan Proteins / genetics*
Protozoan Proteins / metabolism
Saccharomyces cerevisiae / genetics
Saccharomyces cerevisiae / metabolism*
Trypanosoma brucei brucei / growth & development
Trypanosoma brucei brucei / metabolism*
Trypanosoma brucei brucei / ultrastructure
Xenopus laevis

Substances

CLCN6 protein, human
CLCN7 protein, human
Chloride Channels
Chlorides
Nitrates
Protozoan Proteins
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid

Grants and funding

This work was supported by Sinergia grant CRSII3_141913/1 from the Swiss National Science Foundation (http://www.snf.ch) (PB, DR, PM, ES). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.