Open AccessDeterminants for protein translocation across mammalian endoplasmic reticulum
Author(s) -
IBRAHIMI Ibrahim M.,
CUTLER Daniel,
STUEBER Dietrich,
BUJARD Hermann
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09526.x
Subject(s) - endoplasmic reticulum , chromosomal translocation , ribosome , signal recognition particle , microbiology and biotechnology , translocon , biology , signal peptide , chemistry , biochemistry , rna , peptide sequence , gene
The translocation of fragments of prelysozyme lacking varying portions of the COOH terminus of the protein is studied in comparison to full‐length prelysozyme using transcription‐couppled capping of RNA and subsequent translation in a wheat germ cell‐free system. The fragments are generated by restricting cloned lysozyme cDNA at selected sites. We found that fragments of 102 and 74 amino acid residues could still be translocated by mammalian endoplasmic reticulum. Addition of signal‐recognition particles (SRP) to the cell‐free system blocked the nascent chain synthesis. The SRP‐depleted membrane by itself could neither process nor translocate the prepolypeptide chain. The presence of both components was essential for processing and translocation as well as the release of the nascent chain arrest induced by SRP. However, when the size of the fragment was limited to 51 amino acids, the SRP‐induced arrest, the translocation and processing failed to take place. These results define minimum length and structural requirements for translocation of the nascent chain across mammalian endoplasmic reticulum.