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An inhibitory segment within G-patch activators tunes Prp43-ATPase activity during ribosome assembly

ABSTRACT: Mechanisms by which G-patch activators tune the processive multi-tasking ATP-dependent RNA helicase Prp43 to remodel diverse RNA:protein complexes remain elusive. Here, a comparative study between a new activator, Tma23, and a characterized activator, Pxr1, uncovered segments that organize Prp43 function during ribosome assembly. In addition to the activating G-patch, we discovered an inhibitory segment within Tma23 and Pxr1, I-patch, that restrains Prp43-ATPase activity. Cryo-electron microscopy and hydrogen-deuterium exchange mass spectrometry show how I-patch binds to the catalytic RecA-like domains to allosterically inhibit Prp43-ATPase activity. Tma23 and Pxr1 also contain a dimerization segment which organizes Prp43 into higher-order complexes. We posit that Prp43 function at discrete locations on pre-ribosomal RNA are coordinated through toggling interactions with G-patch and I-patch motifs. This could guarantee measured and timely Prp43 activation, enabling precise control over multiple RNA remodeling events occurring concurrently during ribosome formation.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast) Saccharomyces Cerevisiae

SUBMITTER: Oscar Vadas

LAB HEAD: Oscar Vadas

PROVIDER: PXD046892 | Pride | 2024-10-09

REPOSITORIES: Pride

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			Action	DRS
	20220207_OT_HDXMS48.mgf	Mgf
	20220207_OT_HDXMS48.raw	Raw
	20220207_OT_HDXMS57.raw	Raw
	20220207_OT_HDXMS59.raw	Raw
	20220207_OT_HDXMS60.raw	Raw

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An inhibitory segment within G-patch activators tunes Prp43-ATPase activity during ribosome assembly

Project description:Mechanisms by which G-patch activators tune the processive multi-tasking ATP-dependent RNA helicase Prp43 (DHX15 in humans) to productively remodel diverse RNA:protein complexes remain elusive. Here, a comparative study between a new activator, Tma23, and a characterized activator, Pxr1, uncovered segments that organize Prp43 function during ribosome assembly. In addition to the activating G-patch, we discovered an inhibitory segment within Tma23 and Pxr1, I-patch, that restrains Prp43 ATPase activity. Cryo-electron microscopy and hydrogen-deuterium exchange mass spectrometry show how I-patch binds to the catalytic RecA-like domains to allosterically inhibit Prp43 ATPase activity. Tma23 and Pxr1 contain dimerization segments that organize Prp43 into higher-order complexes. We posit that Prp43 function at discrete locations on pre-ribosomal RNA is coordinated through toggling interactions with G-patch and I-patch segments. This could guarantee measured and timely Prp43 activation, enabling precise control over multiple RNA remodelling events occurring concurrently during ribosome formation.

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