Extracellular proteins needed for C. elegans mechanosensation

Neuron. 1996 Jan;16(1):183-94. doi: 10.1016/s0896-6273(00)80035-5.


The mec-5 and mec-9 genes encode putative extracellular proteins that allow a set of six touch receptor neurons in C. elegans to respond to gentle touch. MEC-5 is a collagen made by the epidermal cells that surround the touch cells. Mutations causing touch insensitivity affect the Gly-X-Y repeats of this collagen. mec-9 produces two transcripts, the larger of which is expressed in the touch cells and two PVD neurons. This transcript encodes a protein with 5 Kunitz-type protease inhibitor domains, 6 EGF-like repeats (2 of the Ca(2+)-binding type), and a glutamic acid-rich region. Missense mutations causing touch insensitivity affect both the EGF-like and Kunitz domains. Since mec-9 loss of function mutations dominantly enhance the touch insensitive phenotype of several mec-5 mutations, MEC-5 and MEC-9 may interact. We propose that these proteins provide an extracellular attachment point for the mechanosensory channels of the touch cells.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins*
  • Collagen / genetics
  • Collagen / physiology*
  • Epistasis, Genetic
  • Extracellular Matrix / physiology*
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / physiology*
  • Fluorescent Dyes
  • Genes, Helminth
  • Genes, Recessive
  • Genes, Reporter
  • Helminth Proteins / chemistry
  • Helminth Proteins / genetics
  • Helminth Proteins / physiology*
  • Mechanoreceptors / physiology*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Neurons, Afferent / chemistry
  • Neurons, Afferent / physiology*
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / analysis
  • Repetitive Sequences, Nucleic Acid
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Touch / physiology*


  • Caenorhabditis elegans Proteins
  • Extracellular Matrix Proteins
  • Fluorescent Dyes
  • Helminth Proteins
  • MEC-5 protein, C elegans
  • MEC-9 protein, C elegans
  • Recombinant Fusion Proteins
  • Collagen

Associated data

  • GENBANK/U33918
  • GENBANK/U33919
  • GENBANK/U33933
  • GENBANK/U33934