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PLoS One. 2007 Mar 21;2(3):e303.

MLN51 stimulates the RNA-helicase activity of eIF4AIII.

Author information

1
Laboratory of Macromolecular Structure, Institute of Molecular and Cell Biology, Singapore, Singapore.

Abstract

The core of the exon-junction complex consists of Y14, Magoh, MLN51 and eIF4AIII, a DEAD-box RNA helicase. MLN51 stimulates the ATPase activity of eIF4AIII, whilst the Y14-Magoh complex inhibits it. We show that the MLN51-dependent stimulation increases both the affinity of eIF4AIII for ATP and the rate of enzyme turnover; the K(M) is decreased by an order of magnitude and k(cat) increases 30 fold. Y14-Magoh do inhibit the MLN51-stimulated ATPase activity, but not back to background levels. The ATP-bound form of the eIF4AIII-MLN51 complex has a 100-fold higher affinity for RNA than the unbound form and ATP hydrolysis reduces this affinity. MLN51 stimulates the RNA-helicase activity of eIF4AIII, suggesting that this activity may be functionally important.

PMID:
17375189
PMCID:
PMC1810427
DOI:
10.1371/journal.pone.0000303
[Indexed for MEDLINE]
Free PMC Article

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