Voltage-Dependent Anion Selective Channel Isoforms in Yeast: Expression, Structure, and Functions.

Maria Carmela Di Rosa,Vito De Pinto,Andrea Magrì,Stefano Conti Nibali,Francesca Guarino

doi:10.3389/fphys.2021.675708

Abstract

Mitochondrial porins, also known as voltage-dependent anion selective channels (VDACs), are pore-forming molecules of the outer mitochondrial membranes, involved in the regulation of metabolic flux between cytosol and mitochondria. Playing such an essential role, VDAC proteins are evolutionary conserved and isoforms are present in numerous species. The quest for specific function(s) related to the raise of multiple isoforms is an intriguing theme. The yeast Saccharomyces cerevisiae genome is endowed with two different VDAC genes encoding for two distinct porin isoforms, definitely less characterized in comparison to mammalian counterpart. While yVDAC1 has been extensively studied, the second isoform, yVDAC2, is much less expressed, and has a still misunderstood function. This review will recapitulate the known and poorly known information in the literature, in the light of the growing interest about the features of VDAC isoforms in the cell.

Highlights

The passive diffusion of small hydrophilic molecules throughout outer membranes (OM) of Gramnegative bacteria, mitochondria and chloroplast is provided by the presence of integral membrane proteins commonly named porins
Porins are generally arranged in a conserved β-barrel structure, with polar amino acids facing the hydrophilic compartments counterbalanced by non-polar residues in the hydrophobic membrane core (Benz, 1989; Rosenbusch, 1990; Zeth and Thein, 2010)
In the lights of these considerations, in this review we summarized all the literature information available so far about the structure, the electrophysiological features and the peculiar functions of the two voltage-dependent anion selective channels (VDACs) isoforms expressed by the yeast S. cerevisiae

Summary

Introduction

The passive diffusion of small hydrophilic molecules throughout outer membranes (OM) of Gramnegative bacteria, mitochondria and chloroplast is provided by the presence of integral membrane proteins commonly named porins. In the lights of these considerations, in this review we summarized all the literature information available so far about the structure, the electrophysiological features and the peculiar functions of the two VDAC isoforms expressed by the yeast S. cerevisiae. This isoform has specific and peculiar features: for example, in non-reducing conditions it forms small pores of about 90 pS in artificial membranes (Checchetto et al, 2014) while, in yeast devoid of endogenous porins, it complements the growth defect only partially (Sampson et al, 1997; Reina et al, 2010).

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