Persistent activation of protein kinase Calpha is not necessary for expression of cerebellar long-term depression

Mol Cell Neurosci. 2007 May;35(1):38-48. doi: 10.1016/j.mcn.2007.01.016. Epub 2007 Feb 8.

Abstract

Protein kinase Calpha (PKCalpha) plays a major role in the induction of long-term depression (LTD) in a cerebellar Purkinje cell (PC). The sequential activation model for classical PKC states that PKCalpha translocates to the plasma membrane by binding Ca(++) and then becomes fully activated by binding diacylglycerol (DAG), which enables estimation of the activity by monitoring its localization. Here, we performed simultaneous electrophysiological recording and fluorescence imaging in a cultured PC expressing GFP-tagged PKCalpha. When a PC was depolarized, PKCalpha transiently translocated to the plasma membrane in a Ca(++)-dependent manner. Application of membrane permeable DAG or the blocker of DAG lipase prolonged the translocation. These results suggest that the sequential activation model is applicable to PCs. Conjunctive applications of glutamate and depolarization pulse induced LTD, but did not prolong the translocation. Thus, our results imply that persistent activation of PKCalpha is not necessary for the expression of LTD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Cell Membrane / enzymology
  • Cells, Cultured
  • Cerebellum / cytology
  • Diglycerides / metabolism
  • Green Fluorescent Proteins / genetics
  • Long-Term Synaptic Depression / physiology*
  • Patch-Clamp Techniques
  • Protein Kinase C-alpha / genetics
  • Protein Kinase C-alpha / metabolism*
  • Purkinje Cells / cytology
  • Purkinje Cells / enzymology*
  • Rats
  • Receptors, Metabotropic Glutamate / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism

Substances

  • Diglycerides
  • Receptors, Metabotropic Glutamate
  • Recombinant Proteins
  • metabotropic glutamate receptor type 1
  • Green Fluorescent Proteins
  • Protein Kinase C-alpha
  • Calcium