Genetically encoded reporters of protein kinase A activity reveal impact of substrate tethering

Jin Zhang, Yuliang Ma, Susan S. Taylor, Roger Y. Tsien

Research output: Contribution to journalArticlepeer-review

Abstract

The complexity and specificity of many forms of signal transduction are widely suspected to require spatial microcompartmentation of protein kinase and phosphatase activities, yet current relevant imaging methods such as phosphorylation-specific antibodies or fluorescent peptide substrates require fixation or microinjection and lack temporal or spatial resolution. We present a genetically encoded fluorescent reporter for protein kinase A (PKA) consisting of fusions of cyan fluorescent protein, a phosphoamino acid binding domain (14-3-3τ), a consensus substrate for PKA, and yellow fluorescent protein. cAMP elevations cause 25-50% changes in the ratios of yellow to cyan emissions in live cells caused by phosphorylation-induced changes in fluorescence resonance energy transfer. The reporter response was accelerated by tethering to PKA holoenzyme and slowed by localization to the nucleus. We demonstrate that deliberate redistribution of a substrate or colocalizing a substrate and PKA can modulate its susceptibility to phosphorylation by the kinase. The successful design of a fluorescent reporter of PKA activity and its application for studying compartmentalized and dynamic modulation of kinases lays a foundation for studying targeting and compartmentation of PKA and other kinases and phosphatases.

Original languageEnglish (US)
Pages (from-to)14997-15002
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume98
Issue number26
DOIs
StatePublished - Dec 18 2001
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • General

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