Details

Autor(en) / Beteiligte

• Weghuber, Julian
• Dieterich, Frank
• Froschauer, Elisabeth M
• Svidova, Sona
• Schweyen, Rudolf J

Titel

Mutational analysis of functional domains in Mrs2p, the mitochondrial Mg super(2+) channel protein of Saccharomyces cerevisiae

Ist Teil von

• The FEBS journal, 2006-03, Vol.273 (6), p.1198-1209

Erscheinungsjahr

2006

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The nuclear gene MRS2 in Saccharomyces cerevisiae encodes an integral protein (Mrs2p) of the inner mitochondrial membrane. It forms an ion channel mediating influx of Mg super(2+) into mitochondria. Orthologues of Mrs2p have been shown to exist in other lower eukaryotes, in vertebrates and in plants. Characteristic features of the Mrs2 protein family and the distantly related CorA proteins of bacteria are the presence of two adjacent transmembrane domains near the C terminus of Mrs2p one of which ends with a F-Y-G-M-N motif. Two coiled-coil domains and several conserved primary sequence blocks in the central part of Mrs2p are identified here as additional characteristics of the Mrs2p family. Gain-of-function mutations obtained upon random mutagenesis map to these conserved sequence blocks. They lead to moderate increases in mitochondrial Mg super(2+) concentrations and concomitant positive effects on splicing of mutant group II intron RNA. Site-directed mutations in several conserved sequences reduce Mrs2p-mediated Mg super(2+) uptake. Mutants with strong effects on mitochondrial Mg super(2+) concentrations also have decreased group II intron splicing. Deletion of a nonconserved basic region, previously invoked for interaction with mitochondrial introns, lowers intramitochondrial Mg super(2+) levels as well as group II intron splicing. Data presented support the notion that effects of mutations in Mrs2p on group II intron splicing are a consequence of changes in steady-state mitochondrial Mg super(2+) concentrations.