MICAL1 constrains cardiac stress responses and protects against disease by oxidizing CaMKII

Area of Science:

• Biochemistry
• Molecular Biology
• Physiology

Background:

• Oxidative stress is implicated in various health and disease states.
• Calcium/calmodulin-dependent protein kinase II (CaMKII) plays a crucial role in physiological and pathological processes.
• A conserved redox-sensitive mechanism regulating CaMKII activity is not well understood.

Purpose of the Study:

• To identify and characterize a common stereospecific redox pathway regulating CaMKII activity in invertebrates and vertebrates.
• To investigate the role of this pathway in protecting against pathological stress responses.
• To explore the trade-off between disease protection and physiological performance.

Main Methods:

• Investigated the interaction between MICAL1, MSRB, and CaMKII.
• Analyzed the redox status of a specific methionine residue (M308) in the CaMKII calmodulin-binding domain.
• Utilized mouse models lacking MICAL1, Drosophila melanogaster, and human induced pluripotent stem cell-derived cardiomyocytes.
• Assessed CaMKII activity, CaM binding, cardiac function, and stress responses.

Main Results:

• Identified a stereospecific redox pathway involving MICAL1 and MSRB that controls the oxidation state of M308 in CaMKII.
• Oxidation or mutation of M308 reduces CaM binding and CaMKII activity.
• MICAL1 deficiency in mice leads to cardiac arrhythmias and premature death due to CaMKII hyperactivation.
• Mimicking M308 oxidation impairs fight-or-flight responses in mice and heart function in Drosophila, but protects against disease in human cardiomyocytes with a CaMKII-sensitive arrhythmia.

Conclusions:

• A conserved stereospecific redox pathway regulates CaMKII activity, impacting both physiological performance and pathological stress responses across species.
• This pathway represents a critical link between oxidative stress and cardiac function.
• Understanding this redox regulation offers potential therapeutic targets for CaMKII-related disorders.