Fas ligand is enriched in the caveolae membrane domains of thymic epithelial cells.
Both Fas and Fas ligand (FasL) are expressed in the thymus. Although reports suggest that they are important throughout the thymocyte maturation process their precise role remains elusive. The present paper characterizes the expression of FasL in the thymus and in the TEA3A1 and BT1B functional thymic epithelial cell (TEC) lines. FasL expression by thymus fractions, TEA3A1, and BT1B cells was detected by Northern blot analysis. In TEA3A1 cells, we discovered that FasL protein expression was localized to caveolae membrane domains. This restricted subcellular localization of FasL, together with reports describing the localization of the major histocompatibility complex proteins, the T cell receptor and Fas to caveolae membrane domains, may provide a mechanism for the deletion of thymocytes during negative selection. Finally, using semi-quantitative RT-PCR we found that FasL expression by TECs is regulated by glucocorticoids.
Lalor
Declan
D
Department of Pharmaceutical Sciences, University of Maryland, 20 North Pine Street, Baltimore, MD 21201, USA. declan@hera.med.utoronto.ca
Liu
Pingsheng
P
Hayashi
Jun
J
D000818:Animals; D015152:Blotting, Northern; D021941:Caveolae / Q000378:metabolism*; D002460:Cell Line; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D053222:Fas Ligand Protein; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; C505662:Faslg protein, rat; D005938:Glucocorticoids; D008562:Membrane Glycoproteins; D012333:RNA, Messenger