Tail-anchored protein insertion into yeast ER requires a novel posttranslational mechanism which is independent of the SEC machinery.
Tail-anchored or C-terminally-anchored proteins play many essential roles in eukaryotic cells. However, targeting and insertion of this class of membrane protein has remained elusive. In this study, we reconstitute insertion of tail-anchored proteins into microsomes derived from Saccharomyces cerevisiae. Using this approach, we are able to genetically manipulate the composition of the microsomes in order to address the question of which components of the endoplasmic reticulum (ER) are required for this process. We show that tail-anchored protein insertion is not dependent on the classical SEC translocation machinery but rather occurs via an ATP-dependent pathway involving at least one novel membrane protein factor. We further demonstrate that the specificity of this pathway is conserved between yeast and mammals.
Steel
Gregor J
GJ
School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, U.K.
Brownsword
Judy
J
Stirling
Colin J
CJ
D000255:Adenosine Triphosphate / Q000502:physiology; D010450:Endopeptidases; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins
D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D011498:Protein Precursors; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D000255:Adenosine Triphosphate; D010450:Endopeptidases