3
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Kinetic and mechanistic studies of p38α MAP kinase phosphorylation by MKK6.

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Bistability (coexistence of two stable steady states in a dynamical system) is a key mechanism of cellular decision-making and has been observed in many biochemical reaction networks such as mitogen-activated protein kinase (MAPK) signaling pathways. Theoretical studies have shown that bistability can arise in a single two-site MAPK phosphorylation and dephosphorylation cycle. However, the bistable behavior mostly relies on the kinetic mechanisms and parameters of this two-site modification. In exploring the system-level properties of MAPK regulation, most models to date focus on two limiting reaction regimes, distributive and processive, and are characterized by high levels of parametric uncertainty. Here, we developed a combined kinetic method which applies a continuous spectrophotometric enzyme-coupled assay incorporated with the viscosity approach, to perform detailed kinetic analyses of p38α MAPK dual phosphorylation by MKK6. Almost all kinetic rate constants for the first and second phosphorylation steps in p38α activation have been quantitatively determined, supporting that the phosphorylation occurs randomly in the first step, albeit preferring the tyrosine residue. The release rates of monophosphorylated p38α from MKK6, either as the product in the first modification or as the substrate in the second step, were comparable to the respective adjacent phosphoryl transfer steps. These results indicated that dual phosphorylation of p38α by MKK6 involves a random, partially processive mechanism. Based on the experimentally determined models and parameters, dynamics of the p38α-MKK6-MKP5 system were explored, demonstrating for the first time that bistability can arise with this model at biologically feasible parameter values. ENZYMES: p38α (EC 2.7.11.24); MKK6 (EC 2.7.12.2).

          Related collections

          Author and article information

          Journal
          FEBS J
          The FEBS journal
          Wiley
          1742-4658
          1742-464X
          Mar 2019
          : 286
          : 5
          Affiliations
          [1 ] Key Laboratory of Ministry of Education for Protein Science, School of Life Sciences, Tsinghua University, Beijing, China.
          [2 ] Institute of Molecular Enzymology, Soochow University, Suzhou, China.
          Article
          10.1111/febs.14762
          30663248
          ceedca8d-a681-41cf-8473-5beb601b384b
          History

          dual phosphorylation, MAPK ,bistability,partially processive,kinetic study

          Comments

          Comment on this article