2.1. Materials

Antibodies to NRG-1 (1:1000 dilution for Western blot (WB)) were from Abcam (cat #ab80237, Cambridge, MA, USA). Antibodies to α-tubulin (1:5000 dilution for WB) were from Sigma-Aldrich (Atlanta, GA, USA). Rabbit anti-PP1 antibodies (1:500 dilution for WB) were from Calbiochem (Gibbstown, NJ, USA). Antibodies to CDK9 (1:2000 dilution for WB) were from Santa Cruz Biotechnology (Santa Cruz, CA, USA). Phospho-Thr-186-specific anti-CDK9 antibodies (1:1000 dilution for WB) were a gift from Dr. Qiang Zhou (University of California, Berkeley, CA, USA). Expression vectors for Enhanced Green Fluorescent Protein (EGFP)-fused central domain of NIPP1 (NIPP1-(143-224)) or mNIPP1 (NIPP1-(143–224) V201AF203A (RATA mutant)) were described [22]. mNIPP1 mutated within its RVxF motif has a low binding affinity for PP1 [22]. Anti-NIPP1 antibodies were a gift from Dr. Monique Beullens (University of Leuven, Leuven, Belgium) and were described in [23]. The expression vectors containing NRG-1 promoter (PBS 769) and the NF-κB mutated NRG-1 promoter (PBS 769 NF-κB mut) followed by Lac Z reporter [20] were a gift from Dr. Thomas Schmitt-John (University of Aarhus, Aarhus, Denmark). All salts and other reagents were from Sigma-Aldrich.