Analysis of the interplay of protein biogenesis factors at the ribosome exit site reveals new role for NAC

Nyathi, Yvonne and Pool, Martin R. (2015) Analysis of the interplay of protein biogenesis factors at the ribosome exit site reveals new role for NAC. Journal of Cell Biology, 210 (2). pp. 287-301. ISSN 0021-9525

Full content URL: http://dx.doi.org/10.1083/jcb.201410086

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Abstract

The ribosome exit site is a focal point for the interaction of protein-biogenesis factors that guide the fate of nascent polypeptides. These factors include chaperones such as NAC, N-terminal-modifying enzymes like Methionine aminopeptidase (MetAP), and the signal recognition particle (SRP), which targets secretory and membrane proteins to the ER. These factors potentially compete with one another in the short time-window when the nascent chain first emerges at the exit site, suggesting a need for regulation. Here, we show that MetAP contacts the ribosome at the universal adaptor site where it is adjacent to the α subunit of NAC. SRP is also known to contact the ribosome at this site. In the absence of NAC, MetAP and SRP antagonize each other, indicating a novel role for NAC in regulating the access of MetAP and SRP to the ribosome. NAC also functions in SRP-dependent targeting and helps to protect substrates from aggregation before translocation.

Keywords:Protein biogenesis, Protein targeting, Protein translocation, Ribosome, Signal recognition particle, NAC, JCOpen
Subjects:C Biological Sciences > C130 Cell Biology
Divisions:College of Science > School of Life Sciences
ID Code:27682
Deposited On:21 Jun 2017 08:27

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