PKCepsilon activation induces dichotomous cardiac phenotypes and modulates PKCepsilon-RACK interactions and RACK...

Area of Science:

• Cardiovascular Biology
• Molecular Cell Biology
• Biochemistry

Background:

• Receptors for activated C kinase (RACKs) mediate protein kinase C (PKC) activation.
• The impact of PKC activation on RACK expression and PKC-RACK interactions remains unclear.
• PKCepsilon plays a critical role in cardiac function, with varying activity levels leading to distinct phenotypes.

Purpose of the Study:

• To investigate how protein kinase C (PKC) activation modulates RACK protein expression and PKC-RACK interactions.
• To determine the role of PKCepsilon activity levels in regulating RACK expression and PKC-RACK interactions.
• To elucidate the relationship between PKCepsilon-RACK interactions and cardiac phenotypes.

Main Methods:

• Utilized two PKCepsilon transgenic mouse lines with distinct cardiac phenotypes (cardioprotected vs. hypertrophied).
• Assessed RACK isotype expression and PKC-RACK protein-protein interactions in cardiac tissues.
• Employed dominant-negative PKCepsilon transgenic mice to confirm PKCepsilon activity dependence.

Main Results:

• PKCepsilon activation modulated RACK expression and PKC-RACK interactions in a dose-dependent manner.
• Cardioprotected phenotype: enhanced RACK2 expression and PKCepsilon-RACK2 interactions.
• Hypertrophied phenotype: increased RACK2 and RACK1 expression, with novel PKCepsilon-RACK1 interactions observed.

Conclusions:

• RACK expression is dynamically regulated by PKCepsilon activity.
• Differential PKCepsilon-RACK interactions are crucial determinants of PKCepsilon-dependent cardiac phenotypes.
• Findings provide insights into the molecular mechanisms underlying PKCepsilon-mediated cardiac remodeling and disease.