Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A

Multisite phosphorylation of guanylyl cyclase (GC)-A, also known as NPR-A or NPR1, is required for receptor activation by natriuretic peptides (NPs) because alanine substitutions for the first four GC-A phosphorylation sites produce an enzyme that cannot be stimulated by NPs. In contrast, single Glu...

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Main Authors: Neil M. Otto, Lincoln R. Potter
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-11-01
Series:Frontiers in Molecular Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnmol.2022.1012784/full
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author Neil M. Otto
Lincoln R. Potter
author_facet Neil M. Otto
Lincoln R. Potter
author_sort Neil M. Otto
collection DOAJ
description Multisite phosphorylation of guanylyl cyclase (GC)-A, also known as NPR-A or NPR1, is required for receptor activation by natriuretic peptides (NPs) because alanine substitutions for the first four GC-A phosphorylation sites produce an enzyme that cannot be stimulated by NPs. In contrast, single Glu substitutions for the first six chemically identified GC-A phosphorylation sites to mimic the negative charge of phosphate produced an enzyme that is activated by NPs but had an elevated Michaelis constant (Km), resulting in low activity. Here, we show that vicinal (double adjacent) Glu substitutions for the same sites to mimic the two negative charges of phosphate produced a near wild type (WT) enzyme with a low Km. Unlike the enzyme with single glutamate substitutions, the vicinally substituted enzyme did not require the functionally identified Ser-473-Glu substitution to achieve WT-like activity. Importantly, the negative charge associated with either phosphorylation or glutamate substitutions was required for allosteric activation of GC-A by ATP. We conclude that vicinal Glu substitutions are better phosphomimetics than single Glu substitutions and that phosphorylation is required for allosteric activation of GC-A in the absence and presence of NP. Finally, we suggest that the putative functionally identified phosphorylation sites, Ser-473 in GC-A and Ser-489 in GC-B, are not phosphorylation sites at all.
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spelling doaj.art-67bf5043ab4a415881adca86329bfe792022-12-22T04:34:32ZengFrontiers Media S.A.Frontiers in Molecular Neuroscience1662-50992022-11-011510.3389/fnmol.2022.10127841012784Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-ANeil M. OttoLincoln R. PotterMultisite phosphorylation of guanylyl cyclase (GC)-A, also known as NPR-A or NPR1, is required for receptor activation by natriuretic peptides (NPs) because alanine substitutions for the first four GC-A phosphorylation sites produce an enzyme that cannot be stimulated by NPs. In contrast, single Glu substitutions for the first six chemically identified GC-A phosphorylation sites to mimic the negative charge of phosphate produced an enzyme that is activated by NPs but had an elevated Michaelis constant (Km), resulting in low activity. Here, we show that vicinal (double adjacent) Glu substitutions for the same sites to mimic the two negative charges of phosphate produced a near wild type (WT) enzyme with a low Km. Unlike the enzyme with single glutamate substitutions, the vicinally substituted enzyme did not require the functionally identified Ser-473-Glu substitution to achieve WT-like activity. Importantly, the negative charge associated with either phosphorylation or glutamate substitutions was required for allosteric activation of GC-A by ATP. We conclude that vicinal Glu substitutions are better phosphomimetics than single Glu substitutions and that phosphorylation is required for allosteric activation of GC-A in the absence and presence of NP. Finally, we suggest that the putative functionally identified phosphorylation sites, Ser-473 in GC-A and Ser-489 in GC-B, are not phosphorylation sites at all.https://www.frontiersin.org/articles/10.3389/fnmol.2022.1012784/fullphosphorylationcyclic GMPguanylyl cyclasehypertensionheart failurenatriuretic peptide
spellingShingle Neil M. Otto
Lincoln R. Potter
Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
Frontiers in Molecular Neuroscience
phosphorylation
cyclic GMP
guanylyl cyclase
hypertension
heart failure
natriuretic peptide
title Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
title_full Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
title_fullStr Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
title_full_unstemmed Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
title_short Vicinal glutamates are better phosphomimetics: Phosphorylation is required for allosteric activation of guanylyl cyclase-A
title_sort vicinal glutamates are better phosphomimetics phosphorylation is required for allosteric activation of guanylyl cyclase a
topic phosphorylation
cyclic GMP
guanylyl cyclase
hypertension
heart failure
natriuretic peptide
url https://www.frontiersin.org/articles/10.3389/fnmol.2022.1012784/full
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AT lincolnrpotter vicinalglutamatesarebetterphosphomimeticsphosphorylationisrequiredforallostericactivationofguanylylcyclasea