Different membrane-bound forms of acetylcholinesterase are present at the cell surface of hepatocytes.
In the present study we have determinated the acetylcholinesterase molecular forms present in rat liver hepatocytes; we have also studied the association of acetylcholinesterase with the cell surface of the hepatocytes. Subcellular fractionation indicated that rough endoplasmic reticulum and plasma-membrane-enriched fractions contains G4 and G2 acetylcholinesterase forms bound to membranes. Hepatocytes incubated with phosphatidylinositol-specific phospholipase C released about 70% of the surface acetylcholinesterase. Sedimentation analysis showed that all the solubilized acetylcholinesterase activity comes exclusively from a G2 dimer. The G4 hydrophobic form of acetylcholinesterase accounts for the additional cell-surface activity. The existence of these two forms of acetylcholinesterase on the surface of hepatocytes was further established by analyzing the phosphatidylinositol-specific phospholipase C sensitivity of the acetylcholinesterase molecular forms present in isolated rat liver plasma membranes.
Perelman
A
A
Department of Cell Biology, Faculty of Biological Sciences, Catholic University of Chile, Santiago.
Brandan
E
E
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013499:Surface Properties; D010738:Type C Phospholipases
D000110:Acetylcholinesterase; D010738:Type C Phospholipases