SUMO regulates the assembly and function of a cytoplasmic intermediate filament protein in C. elegans

Dev Cell. 2009 Nov;17(5):724-35. doi: 10.1016/j.devcel.2009.10.005.


Sumoylation is a reversible posttranslational modification that plays roles in many processes, including transcriptional regulation, cell division, chromosome integrity, and DNA damage response. Using a proteomics approach, we identified approximately 250 candidate targets of sumoylation in C. elegans. One such target is the cytoplasmic intermediate filament (cIF) protein named IFB-1, which is expressed in hemidesmosome-like structures in the worm epidermis and is essential for embryonic elongation and maintenance of muscle attachment to the cuticle. In the absence of SUMO, IFB-1 formed ectopic filaments and protein aggregates in the lateral epidermis. Moreover, depletion of SUMO or mutation of the SUMO acceptor site on IFB-1 resulted in a reduction of its cytoplasmic soluble pool, leading to a decrease in its exchange rate within epidermal attachment structures. These observations indicate that SUMO regulates cIF assembly by maintaining a cytoplasmic pool of nonpolymerized IFB-1, and that this is necessary for normal IFB-1 function.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cytoplasm / metabolism*
  • Gene Expression Regulation, Developmental
  • Intermediate Filament Proteins / genetics
  • Intermediate Filament Proteins / metabolism*
  • Protein Folding
  • Proteomics
  • Small Ubiquitin-Related Modifier Proteins / genetics
  • Small Ubiquitin-Related Modifier Proteins / metabolism*


  • Caenorhabditis elegans Proteins
  • IFB-1 protein, C elegans
  • Intermediate Filament Proteins
  • Small Ubiquitin-Related Modifier Proteins