title: Characterization of a divergent Sec61beta gene in microsporidia.
abstract: The general secretory (Sec) pathway is the main mechanism for protein secretion and insertion into endoplasmic reticulum and plasma membrane in prokaryotes and eukaryotes. However, the complete genome of the highly specialized microsporidian parasite Encephalitozoon cuniculi appears to lack a gene for Sec61beta, one of three universally conserved proteins that form the core of the Sec translocon. We have identified a putative, highly divergent homologue of Sec61beta in the genome of another microsporidian, Antonospora locustae, and used this to identify a previously unrecognized Sec61beta in E. cuniculi. The identity of these genes is supported by evidence from secondary structure prediction and gene order conservation. Their functional conservation is confirmed by expressing both microsporidian homologues in yeast, where they are localized to the endoplasmic reticulum and rescue a yeast Sec61beta deletion mutant.
authors.affiliation: Canadian Institute for Advanced Research, Botany Department, University of British Columbia, Vancouver, BC.
authors.forename: Claudio H
authors.initials: CH
authors.lastname: Slamovits
authors.forename: Lena
authors.initials: L
authors.lastname: Burri
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Keeling
mesh_terms: D000595:Amino Acid Sequence; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D016814:Microsporidia / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D017433:Protein Structure, Secondary; D021381:Protein Transport; D000069816:SEC Translocation Channels; D012441:Saccharomyces cerevisiae / Q000166:cytology; D016415:Sequence Alignment
chemical_list: D008565:Membrane Proteins; D000069816:SEC Translocation Channels