Sec62p, a component of the endoplasmic reticulum protein translocation machinery, contains multiple binding sites for the Sec-complex.
SEC62 encodes an essential component of the Sec-complex that is responsible for posttranslational protein translocation across the membrane of the endoplasmic reticulum in Saccharomyces cerevisiae. The specific role of Sec62p in translocation was not known and difficult to identify because it is part of an oligomeric protein complex in the endoplasmic reticulum membrane. An in vivo competition assay allowed us to characterize and dissect physical and functional interactions between Sec62p and components of the Sec-complex. We could show that Sec62p binds via its cytosolic N- and C-terminal domains to the Sec-complex. The N-terminal domain, which harbors the major interaction site, binds directly to the last 14 residues of Sec63p. The C-terminal binding site of Sec62p is less important for complex stability, but adjoins the region in Sec62p that might be involved in signal sequence recognition.
Wittke
S
S
Max-Delbrück-Laboratorium, D-50829 Köln, Germany.
Dünnwald
M
M
Johnsson
N
N
D000595:Amino Acid Sequence; D001665:Binding Sites; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D000069816:SEC Translocation Channels; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism
D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; D000069816:SEC Translocation Channels; C499383:SEC61 protein, S cerevisiae; C074213:SEC62 protein, S cerevisiae; C074215:SEC63 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013762:Tetrahydrofolate Dehydrogenase