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Src homology domains in phospholipase C-gamma1 mediate its anti-apoptotic action through regulating the enzymatic

Xia Liu1, Keqiang Ye

  • 1Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

Journal of Neurochemistry
|April 29, 2005
PubMed

Insights

Phospholipase-gamma1 (PLC-gamma1) protects cells from programmed cell death. Its Src homology (SH) domains are crucial for this anti-apoptotic function, likely by regulating enzymatic activity.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Phospholipase-gamma1 (PLC-gamma1) is known to prevent programmed cell death.
  • The specific role of its Src homology (SH) domains in cell survival is not well understood.

Purpose of the Study:

  • To investigate the function of PLC-gamma1's SH domains in promoting cell survival.
  • To elucidate the mechanism by which PLC-gamma1 exerts its anti-apoptotic effects.

Main Methods:

  • Genetic manipulation of PLC-gamma1, including deletion of specific SH domains (N-SH2, C-SH2, SH3) and creation of a lipase-inactive mutant (LIM).
  • Assessment of anti-apoptotic activity and phospholipase activity in modified PLC-gamma1 cells.
  • Pharmacological inhibition and activation of signaling pathways (PKC, calcium mobilization).

Main Results:

  • Deletion of N-SH2 or both N-SH2 and C-SH2 domains abolished PLC-gamma1's anti-apoptotic activity.
  • Removal of the entire SH domain also inhibited apoptosis, while SH3 domain deletion did not affect this function.
  • Lipase-inactive PLC-gamma1 (LIM) failed to suppress apoptosis, and its enzymatic activity was ablated.
  • Enzymatic activity was comparable in SH3 or whole SH domain-deleted cells but reduced in SH2 domain-deleted or LIM cells.
  • Pharmacological inhibition of PLC-gamma1 reduced anti-apoptotic effects in wild-type and SH3/whole SH domain-deleted cells.
  • Activation of PKC and calcium mobilization promoted survival in SH2 domain-deleted or LIM cells.

Conclusions:

  • PLC-gamma1's SH domains are critical for its anti-apoptotic function.
  • The anti-apoptotic role of PLC-gamma1 appears to be mediated by its enzymatic activity, which is regulated by the SH domains.

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