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Negative Feedbacks by Isoprenoids on a Mevalonate Kinase Expressed in the Corpora Allata of Mosquitoes.

Nyati P, Rivera-Perez C, Noriega FG - PLoS ONE (2015)

Bottom Line: AaMVK exhibited efficient inhibition by GPP and FPP (Ki less than 1 μM), and none by isopentenyl pyrophosphate (IPP) and dimethyl allyl pyrophosphate (DPPM).These results suggest that GPP and FPP might act as physiological inhibitors in the synthesis of isoprenoids in the CA of mosquitoes.Changing MVK activity can alter the flux of precursors and therefore regulate juvenile hormone biosynthesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Florida International University, Miami, FL, 33199, United States of America.

ABSTRACT

Background: Juvenile hormones (JH) regulate development and reproductive maturation in insects. JHs are synthesized through the mevalonate pathway (MVAP), an ancient metabolic pathway present in the three domains of life. Mevalonate kinase (MVK) is a key enzyme in the MVAP. MVK catalyzes the synthesis of phosphomevalonate (PM) by transferring the γ-phosphoryl group from ATP to the C5 hydroxyl oxygen of mevalonic acid (MA). Despite the importance of MVKs, these enzymes have been poorly characterized in insects.

Results: We functionally characterized an Aedes aegypti MVK (AaMVK) expressed in the corpora allata (CA) of the mosquito. AaMVK displayed its activity in the presence of metal cofactors. Different nucleotides were used by AaMVK as phosphoryl donors. In the presence of Mg(2+), the enzyme has higher affinity for MA than ATP. The activity of AaMVK was regulated by feedback inhibition from long-chain isoprenoids, such as geranyl diphosphate (GPP) and farnesyl diphosphate (FPP).

Conclusions: AaMVK exhibited efficient inhibition by GPP and FPP (Ki less than 1 μM), and none by isopentenyl pyrophosphate (IPP) and dimethyl allyl pyrophosphate (DPPM). These results suggest that GPP and FPP might act as physiological inhibitors in the synthesis of isoprenoids in the CA of mosquitoes. Changing MVK activity can alter the flux of precursors and therefore regulate juvenile hormone biosynthesis.

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Inhibition of AaMVK activity by GPP (A), FPP (B) and GGPP (C).The rate of MVK activity was measured at different ATP concentrations, without inhibitors and with several fixed concentration of inhibitors (0–1 μM) and MA (200 μM). Secondary plots of slope versus inhibitor concentration indicated that the Ki values for GPP, FPP and GGPP were respectively 0.55 ± 0.28 μM, 0.44 ± 0.2 μM and 0.93 ± 0.19 μM.
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pone.0143107.g004: Inhibition of AaMVK activity by GPP (A), FPP (B) and GGPP (C).The rate of MVK activity was measured at different ATP concentrations, without inhibitors and with several fixed concentration of inhibitors (0–1 μM) and MA (200 μM). Secondary plots of slope versus inhibitor concentration indicated that the Ki values for GPP, FPP and GGPP were respectively 0.55 ± 0.28 μM, 0.44 ± 0.2 μM and 0.93 ± 0.19 μM.

Mentions: The sensitivity of AaMVK towards several phosphorylated isoprenoids is shown in Fig 4 and Table 1. AaMVK activity was strongly inhibited by long chain isoprenoids. Our results demonstrated that GGPP, FPP and GPP are competitive inhibitors for the binding of ATP to AaMVK. Their inhibitory capacities (Ki) were: GGPP (0.93 ± 0.19 μM), FPP (0.44 ± 0.2 μM) and GPP (0.55 ± 0.28 μM) (S5 Fig). Short chain isoprenoids, such as DMAPP and IPP inhibited only in the micromolar range, with a Ki value greater than 10 μM; while C6 compounds, such as PM and DPM, were not inhibitory.


Negative Feedbacks by Isoprenoids on a Mevalonate Kinase Expressed in the Corpora Allata of Mosquitoes.

Nyati P, Rivera-Perez C, Noriega FG - PLoS ONE (2015)

Inhibition of AaMVK activity by GPP (A), FPP (B) and GGPP (C).The rate of MVK activity was measured at different ATP concentrations, without inhibitors and with several fixed concentration of inhibitors (0–1 μM) and MA (200 μM). Secondary plots of slope versus inhibitor concentration indicated that the Ki values for GPP, FPP and GGPP were respectively 0.55 ± 0.28 μM, 0.44 ± 0.2 μM and 0.93 ± 0.19 μM.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643977&req=5

pone.0143107.g004: Inhibition of AaMVK activity by GPP (A), FPP (B) and GGPP (C).The rate of MVK activity was measured at different ATP concentrations, without inhibitors and with several fixed concentration of inhibitors (0–1 μM) and MA (200 μM). Secondary plots of slope versus inhibitor concentration indicated that the Ki values for GPP, FPP and GGPP were respectively 0.55 ± 0.28 μM, 0.44 ± 0.2 μM and 0.93 ± 0.19 μM.
Mentions: The sensitivity of AaMVK towards several phosphorylated isoprenoids is shown in Fig 4 and Table 1. AaMVK activity was strongly inhibited by long chain isoprenoids. Our results demonstrated that GGPP, FPP and GPP are competitive inhibitors for the binding of ATP to AaMVK. Their inhibitory capacities (Ki) were: GGPP (0.93 ± 0.19 μM), FPP (0.44 ± 0.2 μM) and GPP (0.55 ± 0.28 μM) (S5 Fig). Short chain isoprenoids, such as DMAPP and IPP inhibited only in the micromolar range, with a Ki value greater than 10 μM; while C6 compounds, such as PM and DPM, were not inhibitory.

Bottom Line: AaMVK exhibited efficient inhibition by GPP and FPP (Ki less than 1 μM), and none by isopentenyl pyrophosphate (IPP) and dimethyl allyl pyrophosphate (DPPM).These results suggest that GPP and FPP might act as physiological inhibitors in the synthesis of isoprenoids in the CA of mosquitoes.Changing MVK activity can alter the flux of precursors and therefore regulate juvenile hormone biosynthesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Florida International University, Miami, FL, 33199, United States of America.

ABSTRACT

Background: Juvenile hormones (JH) regulate development and reproductive maturation in insects. JHs are synthesized through the mevalonate pathway (MVAP), an ancient metabolic pathway present in the three domains of life. Mevalonate kinase (MVK) is a key enzyme in the MVAP. MVK catalyzes the synthesis of phosphomevalonate (PM) by transferring the γ-phosphoryl group from ATP to the C5 hydroxyl oxygen of mevalonic acid (MA). Despite the importance of MVKs, these enzymes have been poorly characterized in insects.

Results: We functionally characterized an Aedes aegypti MVK (AaMVK) expressed in the corpora allata (CA) of the mosquito. AaMVK displayed its activity in the presence of metal cofactors. Different nucleotides were used by AaMVK as phosphoryl donors. In the presence of Mg(2+), the enzyme has higher affinity for MA than ATP. The activity of AaMVK was regulated by feedback inhibition from long-chain isoprenoids, such as geranyl diphosphate (GPP) and farnesyl diphosphate (FPP).

Conclusions: AaMVK exhibited efficient inhibition by GPP and FPP (Ki less than 1 μM), and none by isopentenyl pyrophosphate (IPP) and dimethyl allyl pyrophosphate (DPPM). These results suggest that GPP and FPP might act as physiological inhibitors in the synthesis of isoprenoids in the CA of mosquitoes. Changing MVK activity can alter the flux of precursors and therefore regulate juvenile hormone biosynthesis.

Show MeSH