Changes in amounts of polysomes in free, cytoskeleton-bound and membrane-bound populations in Krebs II ascites cells subjected to different growth conditions.

I I36 extract of the PM fraction was dominated by the strong actin band, while the corresponding fraction from ER had a particularly strong band at about 50 kDa. This band was also present in the NP-40 extract but was not observed in the 130 mwKCI extract. One band at about 60 kDa appeared exclusively in the Triton X-lOO/DOC fraction of ER. The results show that the three extracts from the PM-, ERand N-fractions contain different complements of ABPs, and in each case the 130 mwKCI extract contained the largest number. The high content of ABPs in 130 mM-KCI extracts following non-ionic-detergent treatment adds further evidence to earlier observations [ 11 that this extract is enriched in cytoskeletal components. 1. Vedeler, A,, Pryme, I. F. & Hesketh, J. E. (1991) Mol.