Phosphorylation of Ser(19) alters the conformation of tyrosine hydroxylase to increase the rate of phosphorylation of Ser(40).
The effect of phosphorylation on the shape of tyrosine hydroxylase (TH) was studied directly using gel filtration and indirectly using electrospray ionization mass spectrometry. Phosphorylation of Ser(19) and Ser(40) produced a TH molecule with a more open conformation than the non-phosphorylated form. The conformational effect of Ser(19) phosphorylation is less pronounced than that of the Ser(40) phosphorylation. The effect of Ser(19) and Ser(40) phosphorylation appears to be additive. Binding of dopamine produced a more compact form when compared with the non-dopamine-bound TH. The interdependence of Ser(19) and Ser(40) phosphorylation was probed using electrospray ionization mass spectrometry. The rate constants for the phosphorylation of Ser(19) and Ser(40) were determined by electrospray ionization mass spectrometry using a consecutive reaction model. The rate constant for the phosphorylation of Ser(40) is approximately 2- to 3-fold higher if Ser(19) is already phosphorylated. These results suggest that phosphorylation of Ser(19) alters the conformation of tyrosine hydroxylase to allow increased accessibility of Ser(40) to kinases.
Bevilaqua
L R
LR
School of Biomedical Sciences, Faculty of Medicine and Health Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
Graham
M E
ME
Dunkley
P R
PR
von Nagy-Felsobuki
E I
EI
Dickson
P W
PW
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D007700:Kinetics; D013058:Mass Spectrometry; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D012694:Serine / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000737:chemistry / Q000378:metabolism*
D010710:Phosphates; D012694:Serine; D014446:Tyrosine 3-Monooxygenase; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004298:Dopamine