Arabidopsis 3-hydroxy-3-methylglutaryl-CoA reductase is regulated at the post-translational level in response to alterations of the sphingolipid and the sterol biosynthetic pathways.
3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR, EC 1.1.1.34) catalyzes the major rate-limiting step in the mevalonate (MVA) pathway for isoprenoid biosynthesis. Its activity is regulated at different levels, from transcriptional to post-translational. Treatment of Arabidopsis thaliana plants with myriocin, a specific inhibitor of serine palmitoyltransferase (SPT), the first enzyme of sphingolipid biosynthesis, resulted in a concomitant reduction of both HMGR activity and the sterol content, which reveals regulatory cross-talk between these two lipid biosynthesis pathways. Myriocin-induced down-regulation of HMGR activity is exerted at the post-translational level, like the regulatory response of HMGR to enhancement or depletion of the flux through the sterol pathway.
Nieto
Benjamín
B
Departament de Bioquímica i Biologia Molecular, Facultat de Farmacia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain.
Forés
Oriol
O
Arró
Montserrat
M
Ferrer
Albert
A
D017360:Arabidopsis; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013107:Sphingolipids / Q000096:biosynthesis*; D013261:Sterols / Q000096:biosynthesis*
D004791:Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D012333:RNA, Messenger; D013107:Sphingolipids; D013261:Sterols; D006903:Hydroxymethylglutaryl CoA Reductases; C001996:thermozymocidin