The mitochondrial BKCa channel cardiac interactome reveals BKCa association with the mitochondrial import receptor subunit Tom22, and the adenine nucleotide translocator

Jin Zhang; Min Li; Zhu Zhang; Ronghui Zhu; Riccardo Olcese; Enrico Stefani; Ligia Toro

doi:10.1016/j.mito.2016.08.017

The mitochondrial BK_Ca channel cardiac interactome reveals BK_Ca association with the mitochondrial import receptor subunit Tom22, and the adenine nucleotide translocator

Mitochondrion. 2017 Mar:33:84-101. doi: 10.1016/j.mito.2016.08.017. Epub 2016 Aug 31.

Authors

Jin Zhang¹, Min Li², Zhu Zhang², Ronghui Zhu², Riccardo Olcese³, Enrico Stefani³, Ligia Toro⁴

Affiliations

¹ Department of Anesthesiology, Division of Molecular Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Department of Molecular & Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA.
² Department of Anesthesiology, Division of Molecular Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
³ Department of Anesthesiology, Division of Molecular Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Department of Physiology, University of California, Los Angeles, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA; Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, CA, USA.
⁴ Department of Anesthesiology, Division of Molecular Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Department of Molecular & Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA; Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, CA, USA. Electronic address: ltoro@ucla.edu.

Abstract

Mitochondrial BK_Ca channel, mitoBK_Ca, regulates mitochondria function in the heart but information on its protein partnerships in cardiac mitochondria is missing. A directed proteomic approach discovered the novel interaction of BK_Ca with Tom22, a component of the mitochondrion outer membrane import system, and the adenine nucleotide translocator (ANT). The expressed protein partners co-immunoprecipitated and co-segregated into mitochondrial fractions in HEK293T cells. The BK_Ca 50 amino acid splice insert, DEC, facilitated BK_Ca interaction with ANT. Further, BK_Ca transmembrane domain was required for the association with both Tom22 and ANT. The results serve as a working framework to understand mitoBK_Ca import and functional relationships.

Keywords: Adenine nucleotide translocator; BK channel; Heart; Macromolecular complex; MaxiK channel; Mitochondria; Potassium ion channel; Proteomics; Tom22.

MeSH terms

Animals
HEK293 Cells
Humans
Immunoprecipitation
Large-Conductance Calcium-Activated Potassium Channels / metabolism*
Male
Mitochondrial ADP, ATP Translocases / metabolism*
Mitochondrial Membrane Transport Proteins / metabolism*
Mitochondrial Precursor Protein Import Complex Proteins
Mitochondrial Proteins / metabolism*
Myocardium / enzymology*
Protein Binding
Protein Interaction Maps
Proteomics
Rats, Sprague-Dawley

Substances

Large-Conductance Calcium-Activated Potassium Channels
Mitochondrial Membrane Transport Proteins
Mitochondrial Precursor Protein Import Complex Proteins
Mitochondrial Proteins
TOMM22 protein, human
Mitochondrial ADP, ATP Translocases

Grants and funding

R01 HL107418/HL/NHLBI NIH HHS/United States