title: Bacterial transmembrane proteins that lack N-terminal signal sequences.
abstract: Tail-anchored membrane proteins (TAMPs), a class of proteins characterized by their lack of N-terminal signal sequence and Sec-independent membrane targeting, play critical roles in apoptosis, vesicle trafficking and other vital processes in eukaryotic organisms. Until recently, this class of membrane proteins has been unknown in bacteria. Here we present the results of bioinformatic analysis revealing proteins that are superficially similar to eukaryotic TAMPs in the bacterium Streptomyces coelicolor. We demonstrate that at least four of these proteins are bona fide membrane-spanning proteins capable of targeting to the membrane in the absence of their N-terminus and the C-terminal membrane-spanning domain is sufficient for membrane targeting. Several of these proteins, including a serine/threonine kinase and the SecE component of the Sec translocon, are widely conserved in bacteria.
authors.affiliation: Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Arryn
authors.initials: A
authors.lastname: Craney
authors.forename: Kapil
authors.initials: K
authors.lastname: Tahlan
authors.forename: David
authors.initials: D
authors.lastname: Andrews
authors.forename: Justin
authors.initials: J
authors.lastname: Nodwell
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D017386:Sequence Homology, Amino Acid; D048372:Streptomyces coelicolor / Q000378:metabolism; D014461:Ultracentrifugation
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D021382:Protein Sorting Signals