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DIDS (4,4'‐diisothiocyanatostilbene‐2,2'‐disulfonic acid) inhibits an early step of protein translocation across the mammalian ER membrane
Author(s) -
Jungnickel Berit,
Rapoport Tom A.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80235-m
Subject(s) - dids , signal recognition particle , chromosomal translocation , endoplasmic reticulum , microsome , biochemistry , cytosol , transport protein , translocon , chemistry , microbiology and biotechnology , membrane protein , biology , membrane , signal peptide , enzyme , peptide sequence , gene
Protein translocation across the endoplasmic reticulum (ER) membrane of yeast can be inhibited by agents believed to specifically affect the transport of ATP through the membrane (Mayinger P. and Meyer D.I. (1993) EMBO J. 12, 659‐666), suggesting the involvement of a translocation component in the lumen of the ER that binds ATP. We demonstrate that one of the inhibitors, 4.4'‐diisothiocyanatostilbene‐2.2'‐disulfonic acid (DIDS), also affects the translocation of proteins into mammalian microsomes. Translocation is blocked at the point of transfer of the nascent chain from the signal recognition particle (SRP) into the ER‐membrane. We also confirm that photoaffinity‐labelling of microsomes with 8‐azido‐ATP inhibits the same early step of protein translocation. Since this step is reported to not require ATP. these results raise the possibility that, in both cases, factor(s) other than ATP‐binding components of the translocation machinery are perturbed.