Skip to main content
. Author manuscript; available in PMC: 2010 Aug 11.
Published in final edited form as: Biochemistry. 2009 Aug 11;48(31):7441–7447. doi: 10.1021/bi900433y

Figure 8. Model of PACT domain 3 activation of PKR.

Figure 8

Only the C-terminal domains of PACT and PKR are shown. (A) PACT is constituitively phosphorylated on S246. Upon stress, a stress activated protein kinase (SAPK) phosphorylates S287. The S287 phosphorylation is phospho-S246-dependent. (B) Inactive PKR has two binding sites for domain 3 residues. (C) Domain 3 binds to PKR when PACT is phosphorylated at S246. This binding exposes another binding site on PKR. (D) The phosphorylation of S246 is required for SAPK phosphorylation of S287. (E) Once S246 and S287 are both phosphorylated, domain 3 binding to PKR is increased or stabilized, and it activates PKR.