Three ATPase activities have an abnormal developmental time course in trembler sciatic nerves.
Trembler mutant mice are affected by a peripheral neuropathy characterized by hypomyelination, demyelination, and Schwann cell proliferation. In adult mutants, supernumerary Schwann cells form membranous structures known as 'onion-bulb' formations. The activities of the Na+, K+-ATPase and of two ouabain-insensitive Mg2+-ATPases were investigated in sciatic nerves of young and adult mutants. The Na+, K+-ATPase activities were 92 and 76% of the control values in young and adult mutants, respectively. By immunoblot analysis, the alpha-subunit of the Na+, K+-ATPase had an identical apparent molecular weight in controls at both ages and in young mutants. In adult mutants, on the contrary, the alpha-subunit appeared smaller by about 2 kd, similar to that in kidney, indicating that the Na+, K+-ATPase was localized mainly on supernumerary Schwann cells. In addition, in the mutants, the developmental increase of both the mitochondrial and the nonmitochondrial Mg2+-ATPase was abnormally high. We suggest that the abnormal increase of the nonmitochondrial Mg2+-ATPase activity during development reflects an enrichment of that enzyme in 'onion-bulb' formations.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D003711:Demyelinating Diseases / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D008818:Mice, Neurologic Mutants; D008928:Mitochondria / Q000201:enzymology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010523:Peripheral Nervous System Diseases / Q000201:enzymology*; D012584:Sciatic Nerve / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D009419:Nerve Tissue Proteins; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase