G protein-coupled receptor signaling: transducers and effectors.

G protein-coupled receptors (GPCRs) are of considerable interest due to their importance in a wide range of physiological functions and in a large number of Food and Drug Administration (FDA)-approved drugs as therapeutic entities. With continued study of their function and mechanism of action, there is a greater understanding of how effector molecules interact with a receptor to initiate downstream effector signaling. This review aims to explore the signaling pathways, dynamic structures, and physiological relevance in the cardiovascular system of the three most important GPCR signaling effectors: heterotrimeric G proteins, GPCR kinases (GRKs), and ß-arrestins. We will first summarize their prominent roles in GPCR pharmacology before transitioning into less well-explored areas. As new technologies are developed and applied to studying GPCR structure and their downstream effectors, there is increasing appreciation for the elegance of the regulatory mechanisms that mediate intracellular signaling and function.

Biventricular apical thrombi in a patient presenting with new-onset dilated cardiomyopathy.

The diagnosis of an apical left ventricular thrombus in the setting of a dilated cardiomyopathy is not uncommon. However, biventricular apical thrombi in this setting is unusual. We present a case of a 67-year-old man who was admitted with new onset heart failure with biventricular apical thrombus formation in the absence of a hypercoagulable state.