English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Class II transactivator (CIITA), the master regulator of MHC class II (MHC-II) gene transcription, shows a complex behavior in terms of self-association, nucleo-cytoplasmic transport and MHC-II gene transactivation. Here, we analyzed the mechanisms of dominant-negative function and nucleo-cytoplasmic transport of CIITA with emphasis on the role of the C-terminal leucine-rich-repeat (LRR) region in these processes. First, we determined nucleo-cytoplasmic transport of endogenous CIITA and thus validated results obtained with epitope-tagged CIITA constructs. LRR mutations in potential protein-protein contact positions lead to either completely blocked or reduced nuclear import, but can also give rise to increased nuclear export. Surprisingly, N-terminally truncated CIITA mutants show dominant-negative inhibition of wild-type CIITA, whether they are located in the nucleus or in the cytoplasm. Integrity of the LRR is necessary for the dominant-negative function of both types of mutants. LRR mutations are dominant over the effect of an exogenously added N-terminal nuclear localization signal (NLS) leading to cytoplasmic localization. Taken together, our results show that the LRR regulate the function of one or several NLS within CIITA, and control both nuclear import and export. Self-association is not affected in these mutants; we therefore suggest that interaction of the LRR with an unknown protein partner may be necessary for import and transactivation function of CIITA.

Importance of class II transactivator leucine-rich repeats for dominant-negative function and nucleo-cytoplasmic transport