Organization of the phosphoinositide cycle. Assessment of inositol transferase activity in purified plasma membranes

Biochem J. 1993 Feb 15;290 ( Pt 1)(Pt 1):179-83. doi: 10.1042/bj2900179.

Abstract

Experiments were carried out to determine whether or not CDP-diacylglycerol:myo-inositol 3-phosphatidyltransferase (IT) activity (EC 2.7.8.11) could be detected in purified plasma-membrane fractions from WRK-1 rat mammary tumour cells. These cells have previously been shown to have a very active phosphoinositide cycle. Sucrose-density-gradient-purified plasma membranes contained no IT activity that could not be accounted for by endoplasmic-reticulum contamination. However, we also determined that the relative amount of IT activity in endoplasmic reticulum and plasma-membrane fractions could be altered by changing the concentration of detergent in the assay system.

Publication types

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

MeSH terms

  • Animals
  • CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase
  • Cell Fractionation
  • Cell Membrane / enzymology*
  • Centrifugation, Density Gradient
  • Detergents / pharmacology
  • Endoplasmic Reticulum / enzymology
  • Kinetics
  • Mammary Neoplasms, Experimental / enzymology*
  • Membrane Proteins
  • Phosphatidylinositols / metabolism*
  • Phosphotransferases / metabolism*
  • Rats
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / enzymology
  • Transferases (Other Substituted Phosphate Groups)*
  • Tumor Cells, Cultured

Substances

  • Detergents
  • Membrane Proteins
  • Phosphatidylinositols
  • Phosphotransferases
  • Transferases (Other Substituted Phosphate Groups)
  • CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase
  • Cdipt protein, rat