title: The tetratricopeptide repeats of receptors involved in protein translocation across membranes.
abstract: Transport of polypeptides across membranes is a general and essential process in every cell. This process is utilized by molecular machines composed of soluble and membrane-inserted proteins. At least one component of the molecular transport machines present in different membranes contains a subunit with a domain composed of 3 tetratricopeptide repeat (TPR) motifs. These domains are important for protein-protein interaction, for example, recognition of chaperones. To understand the evolution of these TPR domain-containing receptors involved in protein translocation, we inferred their phylogenetic relationships. We show that the evolutionary rate of these TPR domains is reduced when compared with the remaining sequence. The reduction is explained by the interaction of the TPR domains with their substrates. Based on the TPR tree, we propose that Sec72 recognizes Hsp70 and that Tom34 recognizes Hsp90. The phylogeny can further be used to assign the localization of the Toc64 isoforms to mitochondria or chloroplasts. Our findings are discussed in the context of the evolutionary development of translocation systems with focus on the occurrence of Hsp70/Hsp90-recognizing TPR domains in these machineries.
authors: Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna, Medical University of Vienna, Veterinary University of Vienna, Austria.
authors: Thomas
authors: T
authors: Schlegel
authors: Oliver
authors: O
authors: Mirus
authors: Arndt
authors: A
authors: von Haeseler
authors: Enrico
authors: E
authors: Schleiff
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D019143:Evolution, Molecular; D006801:Humans; D016013:Likelihood Functions; D008957:Models, Genetic; D018532:Pisum sativum / Q000737:chemistry; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid; D012441:Saccharomyces cerevisiae / Q000737:chemistry
chemical_list: D011956:Receptors, Cell Surface