Current Biology
Volume 14, Issue 21, 9 November 2004, Pages 1888-1896
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Article
MEC-2 Is Recruited to the Putative Mechanosensory Complex in C. elegans Touch Receptor Neurons through Its Stomatin-like Domain

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Abstract

Background: The response to gentle body touch in C. elegans requires a degenerin channel complex containing four proteins (MEC-2, MEC-4, MEC-6, and MEC-10). The central portion of the integral membrane protein MEC-2 contains a stomatin-like region that is highly conserved from bacteria to mammals. The molecular function of this domain in MEC-2, however, is unknown.

Results: Here, we show that MEC-2 colocalizes with the degenerin MEC-4 in regular puncta along touch receptor neuron processes. This punctate localization requires the other channel complex proteins. The stomatin-like region of MEC-2 interacts with the intracellular cytoplasmic portion of MEC-4. Missense mutations in this region that destroy the interaction also disrupt the punctate localization and degenerin-regulating function of MEC-2. Missense mutations outside this region apparently have no effect on the punctate localization but significantly reduce the regulatory effect of MEC-2 on the MEC-4 degenerin channel. A second stomatin-like protein, UNC-24, colocalizes with MEC-2 in vivo and coimmunoprecipitates with MEC-2 and MEC-4 in Xenopus oocytes; unc-24 enhances the touch insensitivity of temperature-sensitive alleles of mec-4 and mec-6.

Conclusion: Two stomatin homologs, MEC-2 and UNC-24, interact with the MEC-4 degenerin through their stomatin-like regions, which act as protein binding domains. At least in the case of MEC-2, this binding allows its nonstomatin domains to regulate channel activity. Stomatin-like regions in other proteins may serve a similar protein binding function.

Cited by (0)

1

Present address: Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487-0344.

2

Present address: Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520.