Posttranslational modifications of mitochondrial fission and fusion proteins in cardiac physiology and pathophysiology.

Mitochondrial fragmentation frequently occurs in chronic pathological conditions as seen in various human diseases. In fact, abnormal mitochondrial morphology and mitochondrial dysfunction are hallmarks of heart failure (HF) in both human patients and HF animal models. A link between mitochondrial fragmentation and cardiac pathologies has been widely proposed, but the physiological relevance of mitochondrial fission and fusion in the heart is still unclear.

Role of mitochondrial Ca homeostasis in cardiac muscles.

Recent discoveries of the molecular identity of mitochondrial Ca influx/efflux mechanisms have placed mitochondrial Ca transport at center stage in views of cellular regulation in various cell-types/tissues. Indeed, mitochondria in cardiac muscles also possess the molecular components for efficient uptake and extraction of Ca. Over the last several years, multiple groups have taken advantage of newly available molecular information about these proteins and applied genetic tools to delineate the precise mechanisms for mitochondrial Ca handling in cardiomyocytes and its contribution to excitation-contraction/metabolism coupling in the heart.

Adrenergic Regulation of Drp1-Driven Mitochondrial Fission in Cardiac Physio-Pathology.

Abnormal mitochondrial morphology, especially fragmented mitochondria, and mitochondrial dysfunction are hallmarks of a variety of human diseases including heart failure (HF). Although emerging evidence suggests a link between mitochondrial fragmentation and cardiac dysfunction, it is still not well described which cardiac signaling pathway regulates mitochondrial morphology and function under pathophysiological conditions such as HF. Mitochondria change their shape and location via the activity of mitochondrial fission and fusion proteins.

Protein kinase D activation induces mitochondrial fragmentation and dysfunction in cardiomyocytes.

Key Points: Abnormal mitochondrial morphology and function in cardiomyocytes are frequently observed under persistent G protein-coupled receptor (G PCR) stimulation. Cardiac signalling mechanisms for regulating mitochondrial morphology and function under pathophysiological conditions in the heart are still poorly understood. We demonstrate that a downstream kinase of G PCR, protein kinase D (PKD) induces mitochondrial fragmentation via phosphorylation of dynamin-like protein 1 (DLP1), a mitochondrial fission protein.