Tyrosine hydroxylase phosphorylation in vivo

Tyrosine hydroxylase (TH) is the rate‐limiting enzyme in the synthesis of the catecholamines dopamine, noradrenaline and adrenaline. One of the major mechanisms for controlling the activity of TH is protein phosphorylation. TH is phosphorylated at serine residues 8, 19, 31 and 40. There have been a number of previous reviews focused on TH phosphorylation in vitro and in situ. This review on TH phosphorylation in vivo has three main sections focusing on: (1) the methods used to investigate TH phosphorylation in vivo, including the animals used, the sacrifice procedures, the tissue preparation, the measurement of TH protein levels and TH phosphorylation and the measurement of TH activation. (2) The regulation of TH phosphorylation and its consequences in vivo, including the kinases and phosphatases acting on TH, the stoichiometry of TH phosphorylation, the proteins that bind TH and TH subcellular location. (3) The acute and prolonged TH phosphorylation changes in specific catecholaminergic tissues, including the adrenal medulla, the nigrostriatal pathway and the mesolimbic pathway. Tyrosine hydroxylase (TH) is the rate‐limiting enzyme in catecholamine synthesis. Its activity is controlled by protein phosphorylation. This review summarises: The methods used to investigate TH phosphorylation and TH activation in vivo. The in vivo evidence for: Which protein kinases phosphorylate TH? Which protein phosphatases dephosphorylate TH? What is the stoichiometry of pTH? What proteins bind to pTH? Where is pTH localised? What is the nature of TH regulation in different catecholaminergic cells? The time course of TH phosphorylation in vivo in response to stressors activating major catecholaminergic cell groups.