Showing papers on "Protein–protein interaction published in 1984"

A relationship between nuclear poly(adenosine diphosphate ribosylation) and acetylation posttranslational modifications. 2. Histone studies.

Abstract: In the accompanying paper [Malik, N., & Smulson, M. (1984) Biochemistry (preceding paper in this issue)], we report that certain acetylated domains of chromatin were selectively retained by an anti-poly(ADP-Rib) antibody column. In this paper, we describe investigations of this phenomenon at the molecular level of protein interactions. We observed that the majority of endogenously hyperacetylated histones have a high affinity toward the polymer antibody column. It is speculated that these proteins were bound to the column via endogenous poly(adenosine diphosphate ribose) [poly(ADP-Rib)] since the binding was reversed upon treatment of the histones with alkali prior to immunofractionation. In order to analyze the distribution of acetate and poly(ADP-Rib) on histone proteins, [3H]acetylated nuclei were incubated in vitro with [32P]NAD. Acetate was incorporated mainly into H3 and H4 while H1 was the major acceptor protein for poly(ADP-Rib). These results suggest that a correlation may exist in vivo between the two posttranslational modification processes and that identical histone molecules may be accessible to both modifications.

Adenovirus Type 12 Early Region 1 Proteins: A Study of their Subcellular Localization and Protein-Protein Interactions

Abstract: Summary Subcellular fractionation of rat and human cells transformed by the adenovirus type 12 (Ad-12) EcoRI-C DNA fragment showed that the 41000 mol. wt. (41K) E1a and 52K E1b proteins were present in the nucleus and cytoplasm at approximately equal concentrations. The 18K E1b protein was associated with the nuclear, mitochondrial, lysosomal and membrane fractions. The 41K E1a protein was also associated with various cytoskeletal structures (probably microtubules and 10 nm filaments) in Ad-12-transformed cells. The Ad-12 E1 41K and 52K proteins have been partially purified from transformed and infected cells. Using these preparations the 52K protein has been shown to exist under non-reducing conditions and probably in vivo as a 100K dimer stabilized by intermolecular disulphide bonds. The 41K protein bound strongly to histones H1 and H4 but much more weakly to H2A, H2B and H3. It did not interact with other comparable basic proteins or with the cytoskeletal components actin, tropomyosin and calmodulin. Although the 41K E1a protein bound to histones in vitro it is probable that such an interaction may not occur in vivo as very little of the adenovirus protein co-purified with chromatin from transformed cells. None of the Ad-12 E1 proteins showed any ATPase or protein kinase activity.