title: Calmodulin may decrease cell surface sialic acid and be involved in the expression of fibronectin during liver regeneration.
abstract: The decrease of sialic acid in plasma membrane glycoproteins and the expression of cell surface fibronectin were studied during the pre-replicative phase of liver regeneration. The aim of this study was to correlate these cell-surface events to the intracellular surge of calmodulin observed a few hours after partial hepatectomy. The fact that calmodulin decreased the specific activity of UDP-N-acetyl-D-glucosamine 2'-epimerase, a key regulatory enzyme in the biosynthesis of glycoprotein sialic acids, and that trifluoperazine prevented the desialylation indicates that the membrane desialylation is a calmodulin-dependent process. On the other hand, Western blotting using anti-rat fibronectin antibody in trifluoperazine-treated animals suggests that calmodulin may also be involved in the surface expression of fibronectin in regenerating hepatocytes.
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000502:physiology*; D002238:Carbohydrate Epimerases / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D012794:Sialic Acids / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000378:metabolism*
chemical_list: D002147:Calmodulin; D005353:Fibronectins; D012794:Sialic Acids; D012795:Sialoglycoproteins; D002238:Carbohydrate Epimerases; C023223:UDP-N-acetylglucosamine 4-epimerase; D002118:Calcium