LINGO-1 Interacts with WNK1 to Regulate Nogo-induced Inhibition of Neurite Extension

doi:10.1074/jbc.M808751200

LINGO-1 Interacts with WNK1 to Regulate Nogo-induced Inhibition of Neurite Extension*

From the Institute of Neuroscience and Key Laboratory of Molecular Neurobiology, Ministry of Education, Neuroscience Research Center of Changzheng Hospital, Second Military Medical University, Shanghai 200433, China

² To whom correspondence should be addressed:
800 Xiangying Rd., Shanghai, 200433 China.
Fax: 86-21-65492132; E-mail: chenghe{at}smmu.edu.cn.

↵1 Both authors contributed equally to this work.

Abstract

LINGO-1 is a component of the tripartite receptor complexes, which act as a convergent mediator of the intracellular signaling in response to myelin-associated inhibitors and lead to collapse of growth cone and inhibition of neurite extension. Although the function of LINGO-1 has been intensively studied, its downstream signaling remains elusive. In the present study, a novel interaction between LINGO-1 and a serine-threonine kinase WNK1 was identified by yeast two-hybrid screen. The interaction was further validated by fluorescence resonance energy transfer and co-immunoprecipitation, and this interaction was intensified by Nogo66 treatment. Morphological evidences showed that WNK1 and LINGO-1 were co-localized in cortical neurons. Furthermore, either suppressing WNK1 expression by RNA interference or overexpression of WNK1-(123–510) attenuated Nogo66-induced inhibition of neurite extension and inhibited the activation of RhoA. Moreover, WNK1 was identified to interact with Rho-GDI1, and this interaction was attenuated by Nogo66 treatment, further indicating its regulatory effect on RhoA activation. Taken together, our results suggest that WNK1 is a novel signaling molecule involved in regulation of LINGO-1 mediated inhibition of neurite extension.

Footnotes

↵* This work was supported by National Key Basic Research Program 2006CB500702, Ministry of Science and Technology of China Grant 2007CB947100, National Natural Science Foundation Grants 30500151, 30530240, and 30770657, National 863 Program 2006AA02A114, Program for Changjiang Scholars and Innovative Research Team in University IRT0528, and Shanghai Metropolitan Fund for Research and Development Grant 07DJ14005.
↵ The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. 1 and 2.
↵³ The abbreviations used are:

NgR

Nogo-66 receptor

LINGO-1

leucine-rich repeat and Ig domain-containing, Nogo receptor-interacting protein

WNK1

with no lysine [K]

Rho-GDI

GDP dissociation inhibitors of Rho-GTPases

FRET

fluorescence resonance energy transfer

FR

FRET ratio

IHC

immunocytochemistry

YFP

yellow fluorescent protein

GFP

green fluorescent protein

NGF

nerve growth factor

GST

glutathione S-transferase

shRNA

short hairpin RNA

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

siRNA

small interfering RNA.
- Received November 18, 2008.
- Revision received March 30, 2009.