In the compact mRNPs, CERKL interacts with PABP, HSP70 and RPS3 in an mRNA-dependent manner.

A and B) HEK-293T cells were transfected with CERKL-WT (A) or with CERKL-C125W mutant (B). After 48 h, cells were treated with 100 µg/ml cycloheximide and lysates were treated or not with RNase A (100 µg/mL) in the presence of three different concentrations of NaCl (150, 450 and 600 mM, as indicated). Then, the lysates were immunoprecipitated with anti-Flag M2 affinity beads. The co-immunoprecipitated proteins were analyzed by immunoblot using antibodies that recognize eIF3B (only in A), PABP, HSP70, RPS3 and Flag (to detect CERKL-WT and its C125W mutant). In the histograms below, the bands corresponding to the various proteins recovered after the Flag IP, in the presence of RNase A, were quantified with respect to CERKL-WT (A) or CERKL-C125W (B) in each lane. Values are the mean from 4 different experiments. Stars indicate statistically significant differences from the values in the presence of 150 mM NaCl (*p<0.05, **p<0.01 and ***p<0.005).