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Mdm31 protein mediates sensitivity to potassium ionophores but does not regulate mitochondrial morphology or phospholipid trafficking in Schizosaccharomyces pombe
Author(s) -
Ivan Branislav,
Lajdova Dana,
Abelovska Lenka,
Balazova Maria,
Nosek Jozef,
Tomaska Lubomir
Publication year - 2015
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.3062
Subject(s) - nigericin , biology , schizosaccharomyces pombe , saccharomyces cerevisiae , mitochondrion , microbiology and biotechnology , phospholipid , biochemistry , mitochondrial fission , mutant , inner mitochondrial membrane , cardiolipin , schizosaccharomyces , valinomycin , yeast , membrane potential , membrane , gene
Mdm31p is an inner mitochondrial membrane (IMM) protein with unknown function in Saccharomyces cerevisiae . Mutants lacking Mdm31p contain only a few giant spherical mitochondria with disorganized internal structure, altered phospholipid composition and disturbed ion homeostasis, accompanied by increased resistance to the electroneutral K + /H + ionophore nigericin. These phenotypes are interpreted as resulting from diverse roles of Mdm31p, presumably in linking mitochondrial DNA (mtDNA) to the machinery involved in segregation of mitochondria, in mediating cation transport across IMM and in phospholipid shuttling between mitochondrial membranes. To investigate which of the roles of Mdm31p are conserved in ascomycetous yeasts, we analysed the Mdm31p orthologue in Schizosaccharomyces pombe. Our results demonstrate that, similarly to its S. cerevisiae counterpart, Sp Mdm31 is a mitochondrial protein and its absence results in increased resistance to nigericin. However, in contrast to S. cerevisiae , Sz. pombe cells lacking Sp Mdm31 are also less sensitive to the electrogenic K + ionophore valinomycin. Moreover, mitochondria of the fission yeast mdm31Δ mutant display no changes in morphology or phospholipid composition. Therefore, in terms of function, the two orthologous proteins appear to have considerably diverged between these two evolutionarily distant yeast species, possibly sharing only their participation in ion homeostasis. Copyright © 2015 John Wiley & Sons, Ltd.