Important role of junctophilin in nematode motor function

Morikatsu Yoshida, Asako Sugimoto, Yasumi Ohshima, Hiroshi Takeshima

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Junctional complexes between the plasma membrane and endoplasmic/sarcoplasmic reticulum are shared by excitable cells and seem to be the structural ground for cross-talk between cell-surface and intracellular ionic channels. Our current studies have identified junctophilins (JPs) as members of a novel transmembrane protein family in the junctional membrane complex. Biochemical and gene-knockout studies have suggested that JPs contribute to the formation of the junctional membrane complex by spanning the intracellular store membrane and interacting with the plasma membrane. We report here invertebrate JPs in fruit fly and nematode. Three distinct JP subtype genes are found in the mammalian genome, while a single JP gene exists in either invertebrate genome. Mammalian and invertebrate JPs share characteristic structural features, although some intervening sequences are found in invertebrate JPs. A reporter assay indicated that the JP gene is predominantly activated in muscle cells in nematode. Nematodes, in which expression of JP was inhibited by RNA-mediated interference (RNAi), showed hypolocomotion. Taking account of the cell-type-specific expression and data from previous reports, the hypolocomotion is likely to be due to the deficiency of junctional membrane structures and the resulting reduction of Ca2+ signaling during excitation-contraction coupling in muscle cells.

Original languageEnglish
Pages (from-to)234-239
Number of pages6
JournalBiochemical and biophysical research communications
Volume289
Issue number1
DOIs
Publication statusPublished - 2001 Nov 23
Externally publishedYes

Keywords

  • Ca release
  • Endoplasmic reticulum
  • Intracellular Ca store
  • Junctophilin
  • Sarcoplasmic reticulum
  • Subsurface cisternae

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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