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Thymic CD4 T cell selection requires attenuation of March8-mediated MHCII turnover in cortical epithelial cells through CD83.

Authors :
von Rohrscheidt J
Petrozziello E
Nedjic J
Federle C
Krzyzak L
Ploegh HL
Ishido S
Steinkasserer A
Klein L
Source :
The Journal of experimental medicine [J Exp Med] 2016 Aug 22; Vol. 213 (9), pp. 1685-94. Date of Electronic Publication: 2016 Aug 08.
Publication Year :
2016

Abstract

Deficiency of CD83 in thymic epithelial cells (TECs) dramatically impairs thymic CD4 T cell selection. CD83 can exert cell-intrinsic and -extrinsic functions through discrete protein domains, but it remains unclear how CD83's capacity to operate through these alternative functional modules relates to its crucial role in TECs. In this study, using viral reconstitution of gene function in TECs, we found that CD83's transmembrane domain is necessary and sufficient for thymic CD4 T cell selection. Moreover, a ubiquitination-resistant MHCII variant restored CD4 T cell selection in Cd83(-/-) mice. Although during dendritic cell maturation CD83 is known to stabilize MHCII through opposing the ubiquitin ligase March1, regulation of March1 did not account for CD83's TEC-intrinsic role. Instead, we provide evidence that MHCII in cortical TECs (cTECs) is targeted by March8, an E3 ligase of as yet unknown physiological substrate specificity. Ablating March8 in Cd83(-/-) mice restored CD4 T cell development. Our results identify CD83-mediated MHCII stabilization through antagonism of March8 as a novel functional adaptation of cTECs for T cell selection. Furthermore, these findings suggest an intriguing division of labor between March1 and March8 in controlling inducible versus constitutive MHCII expression in hematopoietic antigen-presenting cells versus TECs.<br /> (© 2016 von Rohrscheidt et al.)

Details

Language :
English
ISSN :
1540-9538
Volume :
213
Issue :
9
Database :
MEDLINE
Journal :
The Journal of experimental medicine
Publication Type :
Academic Journal
Accession number :
27503071
Full Text :
https://doi.org/10.1084/jem.20160316