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The properties of phosphodiesterase 11A4 GAF domains are regulated by modifications in its N‐terminal domain
Author(s) -
GrossLangenhoff Marco,
Stenzl Arnulf,
Altenberend Florian,
Schultz Anita,
Schultz Joachim E.
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2008.06319.x
Subject(s) - phosphodiesterase , phosphorylation , pde10a , amino acid , adenylyl cyclase , biochemistry , biology , protein kinase a , kinase , enzyme , cyclic nucleotide , cyclase , nucleotide , gene
The tandem GAF domain of human phosphodiesterase 11A4 (hPDE11A4) requires 72 μ m cGMP for half‐maximal effective concentration (EC 50 ) of a cyanobacterial adenylyl cyclase used as a reporter enzyme. Here we examine whether modifications in the N‐terminus of PDE11A4 affect cGMP signalling. The N‐terminus has two phosphorylation sites for cyclic nucleotide monophosphate‐dependent protein kinases (Ser117, Ser168). Phosphorylation of both by cAMP‐dependent protein kinase decreased the EC 50 value for cGMP from 72 to 23 μ m . Phosphomimetic point mutations (S117D/S167D), which project complete phosphorylation, lowered the EC 50 value to 16 μ m . Structural and sequence data indicate that 196 amino acids precede the start of the GAF domain in hPDE11A4. Removal of 197 amino acids yielded unregulated cyclase activity, whereas truncation by 196 amino acids resulted in a cGMP‐regulated protein with a cGMP EC 50 value of 7.6 μ m . Truncation by 176 amino acids was required for cGMP EC 50 values to decrease to below 10 μ m ; a construct truncated by 168 amino acids had an EC 50 value of 224 μ m . The decrease in EC 50 values was accompanied by a sixfold increase in basal activity; the extent of cGMP stimulation remained unaffected, however. We conclude that N‐terminal modifications strongly affect cGMP regulation of hPDE11A4.