Molecular Basis of the Mechanisms Controlling MASTL

Mol Cell Proteomics. 2020 Feb;19(2):326-343. doi: 10.1074/mcp.RA119.001879. Epub 2019 Dec 18.

Abstract

The human MASTL (Microtubule-associated serine/threonine kinase-like) gene encodes an essential protein in the cell cycle. MASTL is a key factor preventing early dephosphorylation of M-phase targets of Cdk1/CycB. Little is known about the mechanism of MASTL activation and regulation. MASTL contains a non-conserved insertion of 550 residues within its activation loop, splitting the kinase domain, and making it unique. Here, we show that this non-conserved middle region (NCMR) of the protein is crucial for target specificity and activity. We performed a phosphoproteomic assay with different MASTL constructs identifying key phosphorylation sites for its activation and determining whether they arise from autophosphorylation or exogenous kinases, thus generating an activation model. Hydrogen/deuterium exchange data complements this analysis revealing that the C-lobe in full-length MASTL forms a stable structure, whereas the N-lobe is dynamic and the NCMR and C-tail contain few localized regions with higher-order structure. Our results indicate that truncated versions of MASTL conserving a cryptic C-Lobe in the NCMR, display catalytic activity and different targets, thus establishing a possible link with truncated mutations observed in cancer-related databases.

Keywords: Kinases; cancer biology; cell cycle; mitosis; protein phosphatases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Cell Line, Tumor
  • HEK293 Cells
  • Humans
  • Microtubule-Associated Proteins* / chemistry
  • Microtubule-Associated Proteins* / genetics
  • Microtubule-Associated Proteins* / metabolism
  • Phosphorylation
  • Protein-Serine-Threonine Kinases* / chemistry
  • Protein-Serine-Threonine Kinases* / genetics
  • Protein-Serine-Threonine Kinases* / metabolism

Substances

  • Microtubule-Associated Proteins
  • MASTL protein, human
  • Protein-Serine-Threonine Kinases

Associated data

  • PDB/5LOH