Alpha-Helical domains promote translocation of intrinsically disordered polypeptides into the endoplasmic reticulum.

ABSTRACT: Co-translational import into the endoplasmic reticulum (ER) is primarily controlled by N-terminal signal sequences that mediate targeting of the ribosome-nascent chain complex to the Sec61/translocon and initiate the translocation process. Here we show that after targeting to the translocon the secondary structure of the nascent polypeptide chain can significantly modulate translocation efficiency. ER-targeted polypeptides dominated by unstructured domains failed to efficiently translocate into the ER lumen and were subjected to proteasomal degradation via a co-translocational/preemptive pathway. Productive ER import could be reinstated by increasing the amount of alpha-helical domains, whereas more effective ER signal sequences had only a minor effect on ER import efficiency of unstructur

SUBMITTER: Miesbauer M 

PROVIDER: S-EPMC2782031 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature