title: Calmodulin-like activity in a mineralising tissue: the rat molar tooth germ.
abstract: Calmodulin, a calcium binding protein, has been implicated in the regulation of many calcium-dependent biological processes. Since calcium has an important role in hard tissue genesis, both at intra- and extracellular levels, we anticipate that calcium binding proteins may modulate this process. The present study investigated a mineralising tissue, the rat molar tooth germ, to determine the presence of calmodulin-like activity. A heat-treated cell-free extract of tooth germs provided enhancement of Ca2+-dependent Mg2+-ATPase and 3':5'-nucleotide phosphodiesterase activity. No enhancement occurred in the absence of calcium or in the presence of trifluoperazine. SDS-polyacrylamide gel electrophoresis of this extract revealed a protein band of approximately 18,000 mol. wt. These findings indicate the presence of calmodulin-like activity in rat molar tooth germs and support the proposal that calcium and calcium binding proteins, in particular calmodulin, have a major regulatory role in the biology of mineralising tissues.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000818:Animals; D001681:Biological Assay; D017301:Ca(2+) Mg(2+)-ATPase; D002135:Calcium-Binding Proteins / Q000032:analysis*; D000252:Calcium-Transporting ATPases / Q000097:blood; D002147:Calmodulin / Q000032:analysis* / Q000494:pharmacology; D002417:Cattle; D004789:Enzyme Activation; D004910:Erythrocyte Membrane / Q000201:enzymology; D006801:Humans; D008963:Molar / Q000032:analysis*; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D014083:Tooth Germ / Q000032:analysis*
chemical_list: D002135:Calcium-Binding Proteins; D002147:Calmodulin; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases