Premium
In vitro PKA phosphorylation‐mediated human PDE4A4 activation
Author(s) -
Laliberté France,
Liu Susana,
Gorseth Elise,
Bobechko Brian,
Bartlett Adrienne,
Lario Paula,
Gresser Michael J,
Huang Zheng
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02259-7
Subject(s) - phosphorylation , chemistry , divalent , rolipram , sf9 , in vitro , protein subunit , enzyme activator , enzyme , hydrolysis , biochemistry , phosphodiesterase , recombinant dna , spodoptera , organic chemistry , gene
The PDE4 catalytic machinery comprises, in part, two divalent cations in a binuclear motif. Here we report that PDE4A4 expressed in Sf9 cells exhibits a biphasic Mg 2+ dose–response (EC 50 of ∼0.15 and >10 mM) in catalyzing cAMP hydrolysis. In vitro phosphorylation of PDE4A4 by the PKA‐catalytic subunit increases the enzyme's sensitivity to Mg 2+ , leading to 4‐fold increased cAMP hydrolysis without affecting its K m . The phosphorylation also increases the potencies of ( R )‐ and ( S )‐rolipram without affecting CDP‐840 and SB‐207499. The results support that modulating the cofactor binding affinity of PDE4 represents a mechanism for regulating its activity.