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A cunning stunt: an alternative mechanism of eukaryotic translation initiation

A cunning stunt: an alternative mechanism of eukaryotic translation initiation
A cunning stunt: an alternative mechanism of eukaryotic translation initiation
Cell stress activates signaling pathways, allowing cells to choose between survival and apoptosis. Translation plays a critical role in balancing this choice by allowing for rapid and physiologically responsive changes in de novo gene expression. The steady-state abundance of cellular inhibitor of apoptosis 2 (cIAP2) is increased in response to various cell stresses. This modular protein contains baculoviral IAP repeat (BIR) motifs and ubiquitin protein ligase (E3) activity, which allows it to bind directly to caspases and to modulate activation of the transcription factor, nuclear factor kappaB (NF-kappaB). The messenger RNA (mRNA) encoding cIAP2 is a large 5.5-kb transcript, with a highly structured 5' untranslated region (5'UTR) also containing 64 upstream initiation codons ahead of the true start codon. cIAP2 employs an unusual cap-dependent mechanism of ribosome shunting to bypass the majority of the inhibitory elements in the 5'UTR, a mechanism first described for plant pararetroviruses. Furthermore, in mammalian cells, this poorly understood mechanism of translation for cIAP2 is enhanced during mild stress in the absence of pararetrovirus-encoded proteins known to be essential for this process in plant cells. Here, we discuss how cIAP2 might utilize the stress-mediated shunt process in the absence of viral proteins, which suggests a more widespread role for canonical initiation factors, internal ribosome entry sequence-specific trans-acting factors, and mRNA structure in translational control during stress.
pe32
Morley, Simon J.
059a6269-c9e5-4165-8498-238153537ceb
Coldwell, Mark J.
a3432799-ed45-4948-9f7a-2a284d3ec65c
Morley, Simon J.
059a6269-c9e5-4165-8498-238153537ceb
Coldwell, Mark J.
a3432799-ed45-4948-9f7a-2a284d3ec65c

Morley, Simon J. and Coldwell, Mark J. (2008) A cunning stunt: an alternative mechanism of eukaryotic translation initiation. Science Signaling, 1 (25), pe32. (doi:10.1126/scisignal.125pe32).

Record type: Article

Abstract

Cell stress activates signaling pathways, allowing cells to choose between survival and apoptosis. Translation plays a critical role in balancing this choice by allowing for rapid and physiologically responsive changes in de novo gene expression. The steady-state abundance of cellular inhibitor of apoptosis 2 (cIAP2) is increased in response to various cell stresses. This modular protein contains baculoviral IAP repeat (BIR) motifs and ubiquitin protein ligase (E3) activity, which allows it to bind directly to caspases and to modulate activation of the transcription factor, nuclear factor kappaB (NF-kappaB). The messenger RNA (mRNA) encoding cIAP2 is a large 5.5-kb transcript, with a highly structured 5' untranslated region (5'UTR) also containing 64 upstream initiation codons ahead of the true start codon. cIAP2 employs an unusual cap-dependent mechanism of ribosome shunting to bypass the majority of the inhibitory elements in the 5'UTR, a mechanism first described for plant pararetroviruses. Furthermore, in mammalian cells, this poorly understood mechanism of translation for cIAP2 is enhanced during mild stress in the absence of pararetrovirus-encoded proteins known to be essential for this process in plant cells. Here, we discuss how cIAP2 might utilize the stress-mediated shunt process in the absence of viral proteins, which suggests a more widespread role for canonical initiation factors, internal ribosome entry sequence-specific trans-acting factors, and mRNA structure in translational control during stress.

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Published date: 2008

Identifiers

Local EPrints ID: 142021
URI: http://eprints.soton.ac.uk/id/eprint/142021
PURE UUID: 3e1d051d-700e-4a98-b232-11a3a0eaa333
ORCID for Mark J. Coldwell: ORCID iD orcid.org/0000-0002-6243-3886

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Date deposited: 01 Apr 2010 14:38
Last modified: 14 Mar 2024 00:38

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Contributors

Author: Simon J. Morley
Author: Mark J. Coldwell ORCID iD

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