Profilin facilitates PKCε activation by accelerating ATP supply.

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Profilin is known to regulate actin dynamics by catalyzing ADP-ATP exchange.
• Protein kinase C epsilon (PKCε) plays crucial roles in various cellular signaling pathways.

Purpose of the Study:

• To investigate the role of profilin in the activation of protein kinase C epsilon (PKCε).
• To elucidate the mechanism by which profilin influences PKCε activity.

Main Methods:

• Co-immunoprecipitation assays to assess profilin-PKCε association.
• Western blotting and kinase assays to measure PKC activity.
• Cellular knockdown experiments using siRNA to deplete profilin.
• Cell-free assays to analyze the effect of profilin on PKCε activity in response to ATP and activator.

Main Results:

• Profilin associates with PKCε in differentiated PC-12 cells, an interaction modulated by PKC activators and inhibitors.
• Knockdown of profilin attenuates basal and DCP-LA-induced PKC activity, while PKA and CaMKII activities remain unaffected.
• In cell-free systems, profilin enhances DCP-LA-induced PKCε activation in an ATP-dependent manner, shifting the activation curve to lower ATP concentrations.

Conclusions:

• Profilin binds to activated PKCε.
• Profilin facilitates PKCε activation by accelerating the supply of ATP to the enzyme.
• This study reveals a novel function of profilin in regulating kinase activity beyond actin dynamics.