Figure 4.

Interchain communication regulates RQ-PKG1 activity. A, PKG1 domain map showing dimerized active and dead PKG chains. RQ indicates the site of the activating mutation in CNB-A, and DA indicates mutation of the catalytic aspartic acid to alanine, which causes a loss of kinase activity. B and C, 293T cells were cotransfected with Flag-tagged dead PKG1, with or without the RQ mutation, and untagged active RQ-mutant PKG1. In vitro kinase reactions were stopped at 1.5 min to measure the activity of untagged PKG1α R177Q (B) or PKG1β R192Q (C). Data are from three independent protein preparations, with each point representing the average from three kinase reactions for each preparation. Bars show means ± S.D., n = 3. **, p > 0.01 by two-tailed Student's t test.