MCB Accepts, published online ahead of print on 2 November 2009

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Google Scholar Articles by Hennigan, R. F. Articles by Ip, W. PubMed PubMed Citation Articles by Hennigan, R. F. Articles by Ip, W.

 Previous Article  |  Next Article 

Mol. Cell. Biol. doi:10.1128/MCB.00248-09
Copyright (c) 2009, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

FRET Analysis of Merlin Conformational Changes

Robert F. Hennigan, Lauren A. Foster, Mary F. Chaiken, Timmy Mani, Michelle M. Gomes, Andrew B. Herr, and Wallace Ip^*

Departments of Cancer & Cell Biology and Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267

^* To whom correspondence should be addressed. Email: wallace.ip{at}uc.edu.

Neurofibromatosis Type 2 is an inherited autosomal disorder caused by biallelic inactivation of the NF2 tumor suppressor gene. The NF2 gene encodes a 70 kDa protein, merlin, which is a member of the Ezrin-Radixin-Moesin (ERM) family. ERM proteins are believed to be regulated by a transition between a closed conformation, formed by binding of their N-terminal FERM domain and C-terminal tail domain, and an open conformation, in which the two domains do not interact. Previous work suggests that the tumor suppressor function of merlin is similarly regulated and that only the closed form is active. Therefore, understanding the mechanisms that control its conformation is crucial. We have developed a series of probes that measures merlin conformation by fluorescence resonance energy transfer (FRET), both as purified protein and in live cells. Using these tools, we find that merlin exists predominately as a monomer in a stable, closed conformation that is mediated by the central -helical domain. The contribution from the FERM-CTD interaction to the closed conformation appears to be less important. Upon phosphorylation or interaction with an effector protein, merlin undergoes a subtle conformational change, suggesting a novel mechanism that modulates the interaction between the FERM domain and the CTD.