ASSOCIATION OF PROTEIN-KINASE CK2 WITH NUCLEAR MATRIX - INFLUENCE OF METHOD OF PREPARATION OF NUCLEAR MATRIX

Nuclear matrix (NM) plays roles of fundamental structural and function al significance as the site of replication, transcription, and RNA pro cessing and transport, acting as an anchor or attachment site for a va riety of enzymes and other proteins involved in these activities. We h ave previously documented that protein kinase CK2 translocates from th e cytosol to the nucleus, where it associates preferentially with chro matin and NM, in response to certain growth stimuli. Considering that characteristics of the isolated NM can depend on the procedure employe d for its isolation, we compared th ree standard methods for NM prepar ation to confirm the association of intrinsic CK2 with this structure. Our data suggest that the method used for isolating the NM can quanti tatively influence the measurable NM-associated CK2. However, all thre e methods employed yielded qualitatively similar results with respect to the stimulus-mediated modulation of NM-associated CK2, thus further supporting the notion that NM is an important site for physiologicall y relevant functions of CK2. In addition, core filaments and cytoskele ton that were isolated by two of the preparative methods had a small b ur significant level of associated CK2 activity. (C) 1997 Wiley-Liss, Inc.(dagger).