A protein kinase associated with apoptosis and tumor suppression: Structure, activity, and discovery of peptide substrates

Anastasia V. Velentza, Andrew M. Schumacher, Curtis Weiss, Martin Egli, D. Martin Watterson*

*Corresponding author for this work

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

Death-associated protein kinase (DAPK) has been implicated in apoptosis and tumor suppression, depending on cellular conditions, and associated with mechanisms of disease. However, DAPK has not been characterized as an enzyme due to the lack of protein or peptide substrates. Therefore, we determined the structure of DAPK catalytic domain, used a homology model of docked peptide substrate, and synthesized positional scanning substrate libraries in order to discover peptide substrates with Km values in the desired 10 μM range and to obtain knowledge about the preferences of DAPK for phosphorylation site sequences. Mutagenesis of DAPK catalytic domain at amino acids conserved among protein kinases or unique to DAPK provided a link between structure and activity. An enzyme assay for DAPK was developed and used to measure activity in adult brain and monitor protein purification based on the physical and chemical properties of the open reading frame of the DAPK cDNA. The results allow insight into substrate preferences and regulation of DAPK, provide a foundation for proteomic investigations and inhibitor discovery, and demonstrate the utility of the experimental approach, which can be extended potentially to kinase open reading frames identified by genome sequencing projects or functional genetics screens and lacking a known substrate.

Original languageEnglish (US)
Pages (from-to)38956-38965
Number of pages10
JournalJournal of Biological Chemistry
Volume276
Issue number42
DOIs
StatePublished - Oct 19 2001

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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