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A negative regulatory role for Y1111 on the Tie-2 RTK

C Sturk1, H Kim, N Jones

  • 1Molecular and Cellular Biology Research, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.

Cellular Signalling
|December 23, 2009
PubMed

Insights

Investigating the Tie2 receptor tyrosine kinase (RTK), this study reveals that the Y1111 residue in its C-tail is crucial for negative regulation. Mutations at Y1111 enhance Tie2 phosphorylation, kinase activity, and downstream signaling.

Area of Science:

  • Molecular biology
  • Cell signaling
  • Angiogenesis research

Background:

  • Tie2 receptor tyrosine kinase (RTK) is vital for angiogenesis, both normal and pathological.
  • Understanding Tie2 regulation is key for developing therapeutic angiogenic agents.
  • The C-terminal tail of Tie2 is implicated in negative regulation of its signaling.

Purpose of the Study:

  • To investigate the role of the C-tail residue Y1111 in Tie2 signaling and regulation.
  • To elucidate the molecular mechanisms of Tie2 auto-regulation.

Main Methods:

  • Generation of Tie2 receptor point mutants, specifically at the Y1111 site (Y1111F, Y1111D, Y1111E).
  • Assays to measure receptor phosphorylation, kinase activity, and downstream signaling.
  • Limited protease digestion to study receptor conformation changes.

Main Results:

  • Mutation of Y1111 to phenylalanine (Y1111F) increased Tie2 phosphorylation, kinase activity, and downstream signaling.
  • Mutation of Y1111 to aspartate (Y1111D) or glutamate (Y1111E) caused a more significant increase in Tie2 phosphorylation and activity.
  • Protease digestion suggested mutations alter receptor conformation, potentially relieving C-tail-mediated inhibition.

Conclusions:

  • Y1111 is a critical residue for the negative regulation of Tie2 activity.
  • These findings offer insights into the intrinsic auto-regulatory mechanisms of Tie2.
  • Targeting Y1111 could be a strategy for modulating Tie2 activity in therapeutic contexts.

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