Structural studies of purified pig lymph node plasma membrane: association of cytoskeletal compounds with the plasma membrane and the effect of detergent solubilization.

The reproducibility of preparation, stability at 4 degrees C, and detergent solubilization characteristics of plasma membrane vesicles purified from domestic pig mesenteric lymph node tissue have been examined. It was found that 2% (w/v) Nonidet P-40 solubilized 50-60% and 2% (w/v) sodium deoxycholate solubilized 60-70% of the total membrane protein. As judged by 125I-labelled lentil lectin staining of the sodium dodecyl sulfate--polyacrylamide gel electrophoresis patterns, 2% (w/v) Nonidet p-40 solubilized approximately 73%, and 2% (w/v) sodium deoxycholate approximately 82% of the total glycoprotein. Actin and a myosin-like component were identified as major constituents of both the Nonidet P-40 and the sodium deoxycholate insoluble fractions, suggesting the possibility that the detergent-insoluble fraction may represent a membrane-associated cytoskeletal network analogous to that which has been demonstrated for the erythrocyte membrane. Consistent with such an intimate association between actin and the plasma membrane, it was found that very little actin could be eluted from the intact membrane vesicles by dialysis against low ionic strength ATP solutions, 0.6 M KCl, or by incubation with DNase I.