Download MendeleyThe Active Conformation of the PAK1 Kinase Domain
Lei, M., Robinson, M.A., Harrison, S.C.(2005) Structure 13: 769-778
- PubMed: 15893667
- DOI: https://doi.org/10.1016/j.str.2005.03.007
- Primary Citation of Related Structures:
1YHV, 1YHW - PubMed Abstract:
The p21-activated kinases (PAKs) participate in cytoskeletal control networks, downstream of Rho-family GTPases. A structure of PAK1 in an autoregulated, "off" state showed that a regulatory region, N-terminal to the kinase domain, forces the latter into an inactive conformation, prevents phosphorylation of Thr423 in the activation loop, and promotes dimerization. We have now determined structures at 1.8 A resolution for the free PAK1 kinase domain, with a mutation in the active site that blocks enzymatic activity, and for the same domain with a "phosphomimetic" mutation in the activation loop. The two very similar structures show that even in the absence of a phosphorylated Thr423, the kinase has an essentially active conformation. When Cdc42 binds the regulatory region and dissociates the dimer, PAK1 will be in an "intermediate-active" state, with a capacity to phosphorylate itself or other substrates even prior to modification of its activation loop.
Organizational Affiliation:
Laboratory of Molecular Medicine, Children's Hospital, 320 Longwood Avenue, Boston, Massachusetts 02115, USA.
