Title

Methyl farnesoate synthesis in the lobster mandibular organ: The roles of HMG-CoA reductase and farnesoic acid O-methyltransferase

Authors

S. Li; J. A. Friesen; K. C. Holford;D. W. Borst

Comments

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Abbreviated Journal Title

Comp. Biochem. Physiol. A-Mol. Integr. Physiol.

Keywords

3-Hydroxy-3-methylglutaryl-coenzyme A reductase; Farnesoic acid; O-methyltransferase; Methyl farnesoate; Mandibular organ; Mandibular; organ-inhibiting hormone; Phosphorylation; Molecular modeling; JUVENILE-HORMONE SYNTHESIS; 3-HYDROXY-3-METHYLGLUTARYL-COA REDUCTASE; CRYSTAL-STRUCTURE; CANCER-PAGURUS; MEVALONATE PATHWAY; EDIBLE CRAB; CRUSTACEAN; DEGRADATION; INSIGHTS; IDENTIFICATION; Biochemistry & Molecular Biology; Physiology; Zoology

Abstract

Eyestalk ablation (ESA) increases crustacean production of methyl farnesoate (MF), a juvenile hormone-like compound, but the biochemical steps involved are not completely understood. We measured the activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and farnesoic acid O-methyl transferase (FAOMeT), an early step and the last step in MF synthesis. ESA elevated hemolymph levels of MF in male lobsters. Enzyme activity suggested that increased MF production on day one was due largely to elevated HMGR activity while changes in FAOMeT activity closely paralleled changes in MF levels on day 14. Transcript levels for HMGR and FAOMeT changed little on day one, but both increased substantially on day 14. We treated ESA males with a partially purified mandibular organ-inhibiting hormone (MOIH) and observed a significant decline in MF levels, FAOMeT activity, and FAOMeT-mRNA levels after 5 h. However, no effect was observed on HMGR activity or its mRNA indicating that they must be regulated by a separate sinus gland peptide. We confirmed that lobster HMGR was not a phosphoprotein and was not regulated by reversible phosphorylation, an important mechanism for regulating other HMGRs. Nevertheless, molecular modeling indicated that the catalytic mechanisms of lobster and mammalian HMGR were similar.

Journal Title

Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology

Volume

155

Issue/Number

1

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

49

Last Page

55

WOS Identifier

WOS:000273153600008

ISSN

1095-6433

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