title: Interleukin-2 receptor-gamma -dependent endocytosis depends on biotin in Jurkat cells.
abstract: Biotin has been credited with having beneficial effects on immune function despite observations that biotin supplementation causes decreased secretion of interleukin-2. Here this paradox was addressed by determining whether receptor-dependent internalization of interleukin-2 by immune cells depends on biotin. Theoretically, this would be consistent with both decreased net secretion of interleukin-2 by biotin-supplemented cells (causing increased endocytosis) and beneficial effects of biotin on immune function (causing increased receptor signaling). Jurkat cells were cultured in biotin-defined media (25, 250, or 10,000 pM). Secretion of interleukin-2 correlated negatively with biotin supply, but transcriptional activity of the interleukin-2 gene correlated positively with biotin supply, suggesting that decreased secretion of interleukin-2 by biotin-supplemented cells was not caused by decreased gene expression. Expression of the interleukin-2 receptor-gamma gene was greater at 10,000 pM than 25 pM biotin, mediating increased endocytosis of interleukin-2 in biotin-supplemented medium. Inhibition of endocytosis by genistein and overexpression of interleukin-2 receptor-gamma abolished the effect of biotin. These findings suggest that endocytosis of interleukin-2 depends on biotin.
authors.affiliation: Department of Nutritional Science and Dietetics, University of Nebraska at Lincoln, Lincoln, Nebraska 68583, USA.
authors.forename: Rocio
authors.initials: R
authors.lastname: Rodriguez-Melendez
authors.forename: Gabriela
authors.initials: G
authors.lastname: Camporeale
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Griffin
authors.forename: Janos
authors.initials: J
authors.lastname: Zempleni
mesh_terms: D001710:Biotin / Q000172:deficiency* / Q000494:pharmacology; D002262:Carboxy-Lyases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D005822:Genetic Vectors; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism*; D019169:Jurkat Cells; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D043586:Methylmalonyl-CoA Decarboxylase; D015375:Receptors, Interleukin-2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D001710:Biotin; D002262:Carboxy-Lyases; D043586:Methylmalonyl-CoA Decarboxylase