PKA catalytic subunit translocates to the nucleus Authored: Le Novere, N, Jassal, B, 2004-03-31 12:22:05 Edited: Jassal, B, 2008-11-06 10:17:49 Reactome Database ID Release 43111924 Reactome, http://www.reactome.org ReactomeREACT_1031 Reviewed: Castagnoli, L, 2008-11-06 12:55:54 When cAMP level rises, the PKA catalytic subunit (C subunit) released from the holoenzyme enters the nucleus by passive diffusion whereas termination of signaling to the nucleus involves an active mechanism. In the nucleus, the C subunit binds to the heat-stable protein kinase inhibitor (PKI), and this binding not only inactivates the C subunit but also by conformational change unveils a nuclear export signal in PKI which leads to export of the C-PKI complex from the nucleus. PKA catalytic subunit PKA catalytic subunits