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A family of ras-like GTP-binding proteins expressed in electromotor neurons

J K Ngsee1, L A Elferink, R H Scheller

  • 1Department of Biological Sciences, Stanford University, California 94305-5020.

The Journal of Biological Chemistry
|February 5, 1991
PubMed

Insights

Researchers identified seven low molecular weight GTP-binding proteins in the marine ray Discopyge ommata. These proteins, including novel ones similar to yeast SEC4, are concentrated in neural tissues and synaptic vesicles.

Area of Science:

  • Molecular Biology
  • Neuroscience
  • Marine Biology

Background:

  • Low molecular weight GTP-binding proteins regulate fundamental cellular processes.
  • These proteins play crucial roles in intracellular trafficking and signaling pathways.
  • Understanding their diversity and function is key in various biological systems.

Purpose of the Study:

  • To identify and characterize low molecular weight (LMW) GTP-binding proteins from the marine ray Discopyge ommata.
  • To investigate the tissue distribution and subcellular localization of these identified proteins.
  • To explore potential roles in neural tissues and synaptic function.

Main Methods:

  • cDNA library screening from Discopyge ommata electrode lobe.
  • Homology analysis to identify known and novel GTP-binding proteins.
  • Northern blot analysis for transcript expression patterns.
  • Affinity purification of antibodies for protein detection.
  • Subcellular fractionation and immunohistochemistry for localization studies.

Main Results:

  • Seven LMW GTP-binding protein cDNAs were isolated, including homologs of rab1, ral, Krev, and rho.
  • Three novel sequences were identified, two with similarity to yeast SEC4.
  • Transcripts were enriched in neural tissues and moderately expressed in cardiac muscle.
  • Proteins co-purified with cholinergic synaptic vesicles and localized to pre-synaptic terminals.

Conclusions:

  • Discopyge ommata possesses a diverse set of LMW GTP-binding proteins, including novel homologs.
  • These proteins are predominantly expressed in neural tissues and are associated with synaptic vesicles.
  • The findings suggest a significant role for these proteins in synaptic function in marine rays.

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