About this item:

337 Views | 674 Downloads

Author Notes:

Address correspondence to: Guy Benian (pathgb@emory.edu).

We thank Henry Epstein (deceased), Shohei Mitani, Robert Waterston, and Phil Anderson for various nematode strains. We also thank Robert Barstead for the C. elegans yeast two-hybrid library RB2, Andrew Fire for pPD49.78 and pPD49.83, and Victor Faundez for plasmid pGBKT7. Some of the nematode strains used in this work were provided by the Caenorhabditis Genetics Center (funded by the National Institutes of Health, Center for Research Resources).

Subjects:

Research Funding:

This study was supported in part by National Institutes of Health Grant R01AR064307 and a pilot grant from Merial Limited to G.M.B.

This study was also supported in part by the Emory Integrated Genomics Core, which is subsidized by the Emory University School of Medicine and is one of the Emory Integrated Core Facilities.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Cell Biology
  • BODY-WALL MUSCLE
  • THICK FILAMENTS
  • KINASE DOMAINS
  • SKELETAL-MUSCLE
  • MYOSIN ROD
  • C-ELEGANS
  • SARCOPLASMIC-RETICULUM
  • SMALL ANKYRIN-1
  • M-LINES
  • MUTANTS

The SH3 domain of UNC-89 (obscurin) interacts with paramyosin, a coiled-coil protein, in Caenorhabditis elegans muscle

Show all authors Show less authors

Tools:

Journal Title:

Molecular Biology of the Cell

Volume:

Volume 27, Number 10

Publisher:

, Pages 1606-1620

Type of Work:

Article | Final Publisher PDF

Abstract:

UNC-89 is a giant polypeptide located at the sarcomeric M-line of Caenorhabditis elegans muscle. The human homologue is obscurin. To understand how UNC-89 is localized and functions, we have been identifying its binding partners. Screening a yeast two-hybrid library revealed that UNC-89 interacts with paramyosin. Paramyosin is an invertebrate-specific coiled-coil dimer protein that is homologous to the rod portion of myosin heavy chains and resides in thick filament cores. Minimally, this interaction requires UNC- 89's SH3 domain and residues 294-376 of paramyosin and has a KD of ∼1.1 μM. In unc-89 loss-of-function mutants that lack the SH3 domain, paramyosin is found in accumulations. When the SH3 domain is overexpressed, paramyosin is mislocalized. SH3 domains usually interact with a proline-rich consensus sequence, but the region of paramyosin that interacts with UNC-89's SH3 is α-helical and lacks prolines. Homology modeling of UNC-89's SH3 suggests structural features that might be responsible for this interaction. The SH3-binding region of paramyosin contains a "skip residue," which is likely to locally unwind the coiled-coil and perhaps contributes to the binding specificity.

Copyright information:

© 2016 Qadota et al.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License (http://creativecommons.org/licenses/by-nc-sa/3.0/).

Creative Commons License

Export to EndNote