1. Thyroid hormone regulation of nuclear-encoded mitochondrial inner membrane polypeptides of the liver.
- Author
-
Joste V, Goitom Z, and Nelson BD
- Subjects
- Animals, Cell Nucleus drug effects, Enzymes biosynthesis, Enzymes genetics, Enzymes isolation & purification, Intracellular Membranes metabolism, Male, Membrane Proteins biosynthesis, Membrane Proteins isolation & purification, Mitochondria, Liver drug effects, RNA, Messenger drug effects, RNA, Messenger genetics, Rats, Rats, Inbred Strains, Reference Values, Submitochondrial Particles drug effects, Cell Nucleus metabolism, Hypothyroidism metabolism, Membrane Proteins genetics, Mitochondria, Liver metabolism, Protein Biosynthesis drug effects, Submitochondrial Particles metabolism, Triiodothyronine pharmacology
- Abstract
The effects of thyroid hormone on nuclear-encoded mitochondrial inner membrane proteins were investigated by in vitro translation of the endogenous mRNA present in a postmitochondrial fraction from the livers of rats treated in vivo with hormone. The levels of the mRNAs were estimated by quantitative immunoabsorption of the translation mixture. Total protein synthesis was increased 2.6-fold after 4 days of in vivo hormone treatment, but only 10-15% of the polypeptides were dramatically altered (greater than 5-fold). Among the most highly elevated were cytochrome c1 (greater than 10-fold increase) and the Rieske iron-sulfur protein of the cytochrome bc1 complex. Other inner membrane proteins (core protein 1, beta subunit of F1 ATPase, subunit IV of cytochrome oxidase, 3-hydroxybutyrate dehydrogenase) and non-mitochondrial proteins (rat serum albumin, beta 2-microglobulin) were not altered significantly by hormone treatment. Cytochrome c1 and the Rieske protein increased after 12 h of hormone treatment, a relatively early response in mammalian mitochondrial biogenesis. The possible significance of this response for the regulation of mitochondrial synthesis and assembly is discussed.
- Published
- 1989
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