UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

The Rac-GAP alpha2-Chimaerin Signals via CRMP2 and Stathmins in the Development of the Ocular Motor System

Carretero-Rodriguez, L; Guðjónsdóttir, R; Poparic, I; Reilly, ML; Chol, M; Bianco, IH; Chiapello, M; ... Guthrie, S; + view all (2021) The Rac-GAP alpha2-Chimaerin Signals via CRMP2 and Stathmins in the Development of the Ocular Motor System. The Journal of Neuroscience , 41 (31) pp. 6652-6672. 10.1523/JNEUROSCI.0983-19.2021. Green open access

[thumbnail of Bianco_6652.full.pdf]
Preview
Text
Bianco_6652.full.pdf

Download (8MB) | Preview

Abstract

A precise sequence of axon guidance events is required for the development of the ocular motor system. Three cranial nerves grow towards, and connect with, six extraocular muscles in a stereotyped pattern, in order to control eye movements. The signalling protein alpha2-chimaerin (α2-CHN) plays a pivotal role in the formation of the ocular motor system; mutations in CHN1, encoding α2-CHN, cause the human eye movement disorder Duane Retraction Syndrome (DRS). Our research has demonstrated that manipulation of α2-chn signalling in the zebrafish embryo leads to ocular motor axon wiring defects, although the signalling cascades regulated by α2-chn remain poorly understood. Here, we demonstrate that several cytoskeletal regulatory proteins - collapsin response mediator protein 2 (CRMP2), (encoded by the gene dpysl2), stathmin1 and stathmin 2 - bind to α2-CHN. dpysl2, stathmin1 and especially stathmin2 are expressed by ocular motor neurons. We find that manipulation of dpysl2 and of stathmins in zebrafish larvae leads to defects in both the axon wiring of the ocular motor system and the optokinetic reflex, impairing horizontal eye movements. Knockdowns of these molecules in zebrafish larvae of either sex caused axon guidance phenotypes that included defasciculation and ectopic branching; in some cases these phenotypes were reminiscent of DRS. chn1 knockdown phenotypes were rescued by overexpression of CRMP2 and STMN1, suggesting that these proteins act in the same signalling pathway. These findings suggest that CRMP2 and stathmins signal downstream of α2-CHN to orchestrate ocular motor axon guidance, and to control eye movements.Significance statementThe precise control of eye movement is crucial for the life of vertebrate animals, including humans. In humans, this control depends on the arrangement of nerve wiring of the ocular motor system, composed of three nerves and six muscles, a system that is conserved across vertebrate phyla. Mutations in the protein alpha2-chimaerin have previously been shown to cause eye movement disorders (squint) and axon wiring defects in humans. Our recent work has unravelled how alpha2-chimaerin co-ordinates axon guidance of the ocular motor system in animal models. In this paper, we demonstrate key roles for the proteins CRMP2 and stathmin 1/2 in the signalling pathway orchestrated by alpha2-chimaerin, potentially giving insight into the aetiology of eye movement disorders in humans.

Type: Article
Title: The Rac-GAP alpha2-Chimaerin Signals via CRMP2 and Stathmins in the Development of the Ocular Motor System
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1523/JNEUROSCI.0983-19.2021
Publisher version: https://doi.org/10.1523/JNEUROSCI.0983-19.2021
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: ocular motor system, alpha2-chimaerin, chimaerin, CRMP2, stathmin
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology
URI: https://discovery.ucl.ac.uk/id/eprint/10131699
Downloads since deposit
8Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item