The role of mammalian PPR domain proteins in the regulation of mitochondrial gene expression

Pentatricopeptide repeat (PPR) domain proteins are a large family of RNA-binding proteins that are involved in the maturation and translation of organelle transcripts in eukaryotes. They were first identified in plant organelles and their important role in mammalian mitochondrial gene regulation is now emerging. Mammalian PPR proteins, like their plant counterparts, have diverse roles in mitochondrial transcription. RNA metabolism and translation and consequently are important for mitochondrial function and cell health. Here we discuss the current knowledge about the seven mammalian PPR proteins identified to date and their roles in the regulation of mitochondria] gene expression. Furthermore we discuss the mitochondrial RNA targets of the mammalian PPR proteins and methods to investigate the RNA targets of these mitochondria] RNA-binding proteins. This article is part of a Special Issue entitled: Mitochondrial Gene Expression. (C) 2011 Elsevier B.V. All rights reserved.