Effects of ATP depletion and protein synthesis inhibition on muscle plasma membrane orthogonal arrays.
We studied the effects of perturbations on the orthogonal arrays of 6- to 8-nm intramembranous particles seen in freeze-fractured fast-twitch rat muscle plasma membrane. We found the arrays to be stable in whole muscle in vitro to 8 to 12 h regardless of the presence of glucose, calcium, or supplemental oxygen. Depletion of ATP with 2,4-dinitrophenol or sodium azide led to a marked reduction in array density without a compensatory increase in nonarray particles. Ninety-five percent inhibition of protein synthesis with cycloheximide had no effect on the arrays to 12 h. These results indicate that muscle plasma membrane orthogonal arrays, if protein, are slow-turn-over structures whose degradation is hastened by ATP depletion.
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D003513:Cycloheximide / Q000494:pharmacology*; D005614:Freeze Fracturing; D008297:Male; D008854:Microscopy, Electron; D009045:Motor Endplate / Q000378:metabolism / Q000648:ultrastructure*; D009132:Muscles / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D009469:Neuromuscular Junction / Q000648:ultrastructure*; D014176:Protein Biosynthesis / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
D000255:Adenosine Triphosphate; D003513:Cycloheximide