Beta-Adrenergic Receptor Kinase (BARK) is a critical enzyme in the regulation of beta-adrenergic receptor (beta-AR) signaling and receptor desensitization. It is a member of the AGC kinase family that includes protein kinase A (PKA), protein kinase C (PKC) and others. BARK is responsible for phosphorylating the carboxyl tail of beta-ARs, resulting in desensitization of the receptor to its ligand. This is an important process in the regulation of catecholamine signaling, allowing for fine-tuning of the response to catecholamines in the body.
BARK has been studied in a number of systems, including the human myocardium, platelets, adipocytes, and lymphocytes. In the myocardium, BARK is believed to play an important role in regulating the contractility of cardiac muscle cells, and has been implicated in a variety of pathological states, including heart failure and cardiac hypertrophy. In platelets, BARK is involved in mediating the platelet aggregation response to thrombin and other agonists. In adipocytes, BARK is believed to regulate the sensitivity of beta-ARs to catecholamines, and thus plays an important role in adipose tissue metabolism. Finally, in lymphocytes, BARK is believed to play a role in the regulation of T-cell receptor signaling.
The structure of BARK has been studied in several systems, and is composed of two domains, an N-terminal kinase domain and a C-terminal regulatory domain. The N-terminal kinase domain is responsible for the phosphorylation of the carboxyl tail of beta-ARs, while the C-terminal regulatory domain is responsible for regulating the activity of the N-terminal domain. BARK is regulated by a variety of factors, including phosphorylation by protein kinase A, protein kinase C, and calcium/calmodulin-dependent kinase II (CaMKII).
BARK is a key enzyme in the regulation of beta-AR signaling and receptor desensitization. Its activity is regulated by a variety of factors, and its structure consists of two domains, an N-terminal kinase domain and a C-terminal regulatory domain. BARK plays an important role in a variety of physiological processes, including heart contractility, platelet aggregation, adipose tissue metabolism, and T-cell receptor signaling.
References
Lefkowitz, R. J., & Shenoy, S. K. (2005). β-Adrenergic receptor kinase: Structure, regulation, and physiological functions. Annual review of physiology, 67(1), 579–599. https://doi.org/10.1146/annurev.physiol.67.031103.145056
Hofmann, F., & Herrmann, A. (2005). Beta-adrenergic receptor kinase (BARK): Regulation and function. Cellular and molecular life sciences, 62(13), 1495–1504. https://doi.org/10.1007/s00018-005-5057-2
Ling, L., Chaudhuri, G., & Lefkowitz, R. J. (1998). Chemical biology of β-adrenergic receptor kinase. Trends in pharmacological sciences, 19(8), 279–286. https://doi.org/10.1016/S0165-6147(98)01254-3