MCT1 and its accessory protein CD147 are differentially regulated by TSH in rat thyroid cells.
In thyroid cells, basal and TSH-stimulated glycolysis is associated with lactic acid efflux. In this report, we address whether monocarboxylate transporters (MCTs) are present in thyroid tissue for exporting excess lactic acid generated by aerobic glycolysis. Using immunostaining techniques, we show that MCT4 localizes with its accessory protein CD147 in the basolateral membrane of rat thyroid follicular cells. In cultured rat thyroid (FRTL-5) cells, MCT1 rather than MCT4 is expressed. CD147 colocalizes and coimmunoprecipitates with MCT1. TSH upregulates MCT1/CD147 expression as a function of time through a cAMP-dependent mechanism as forskolin reproduces the effect of TSH. TSH enhances protein expression of both MCT1 and CD147 in FRTL-5 cells. Whereas MCT1 protein expression is controlled at the level of transcription, CD147 protein expression is regulated by a posttranscriptional mechanism. Results of these studies suggest that hormone stimulation of lactate transport is mediated by regulating MCT1 transcription.
Fanelli
Albertina
A
Laboratory of Biochemical Pharmacology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Grollman
Evelyn F
EF
Wang
Dian
D
Philp
Nancy J
NJ
D000818:Animals; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D051926:Basigin; D001798:Blood Proteins; D002460:Cell Line; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D027981:Symporters / Q000378:metabolism*; D013961:Thyroid Gland / Q000166:cytology* / Q000378:metabolism*; D013972:Thyrotropin / Q000378:metabolism*; D014018:Tissue Distribution; D000099233:Monocarboxylate Transport Protein 1
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D051926:Basigin; D001798:Blood Proteins; D008562:Membrane Glycoproteins; D027501:Monocarboxylic Acid Transporters; D027981:Symporters; D013972:Thyrotropin; D000099233:Monocarboxylate Transport Protein 1; C102624:Bsg protein, Gallus gallus; C079432:Bsg protein, rat