The adaptive immune response critically hinges on the functionality of T cell receptors, governed by complex molecular mechanisms, including ubiquitination. In this study, we delved into the role of in T cell immunity, focusing on T cell-B cell conjugate formation and T cell activation. Using a CRISPR-Cas9 screening approach targeting deubiquitinases genes in Jurkat T cells, we identified BAP1 as a key positive regulator of T cell-B cell conjugate formation. Subsequent investigations into BAP1 knockout cells revealed impaired T cell activation, evidenced by decreased MAPK and NF-kB signaling pathways and reduced CD69 expression upon T cell receptor stimulation. Flow cytometry and qPCR analyses demonstrated that BAP1 deficiency leads to decreased surface expression of T cell receptor complex components and reduced mRNA levels of the co-stimulatory molecule CD28. Notably, the observed phenotypes associated with BAP1 knockout are specific to T cells and fully dependent on BAP1 catalytic activity. In-depth RNA-seq and mass spectrometry analyses further revealed that BAP1 deficiency induces broad mRNA and protein expression changes. Overall, our findings elucidate the vital role of BAP1 in T cell biology, especially in T cell-B cell conjugate formation and T cell activation, offering new insights and directions for future research in immune regulation.

• MeSH
• aktivace lymfocytů * imunologie   MeSH
• B-lymfocyty * imunologie   metabolismus   MeSH
• Jurkat buňky MeSH
• lidé MeSH
• nádorové supresorové proteiny * metabolismus   genetika   MeSH
• receptory antigenů T-buněk * metabolismus   MeSH
• signální transdukce MeSH
• T-lymfocyty * imunologie   metabolismus   MeSH
• thiolesterasa ubikvitinu * genetika   metabolismus   nedostatek   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Nuclear deubiquitinase BAP1 (BRCA1-associated protein 1) is a core component of multiprotein complexes that promote transcription by reversing the ubiquitination of histone 2A (H2A). BAP1 is a tumor suppressor whose germline loss-of-function variants predispose to cancer. To our knowledge, there are very rare examples of different germline variants in the same gene causing either a neurodevelopmental disorder (NDD) or a tumor predisposition syndrome. Here, we report a series of 11 de novo germline heterozygous missense BAP1 variants associated with a rare syndromic NDD. Functional analysis showed that most of the variants cannot rescue the consequences of BAP1 inactivation, suggesting a loss-of-function mechanism. In T cells isolated from two affected children, H2A deubiquitination was impaired. In matching peripheral blood mononuclear cells, histone H3 K27 acetylation ChIP-seq indicated that these BAP1 variants induced genome-wide chromatin state alterations, with enrichment for regulatory regions surrounding genes of the ubiquitin-proteasome system (UPS). Altogether, these results define a clinical syndrome caused by rare germline missense BAP1 variants that alter chromatin remodeling through abnormal histone ubiquitination and lead to transcriptional dysregulation of developmental genes.

• MeSH
• chromatin chemie   imunologie   MeSH
• dítě MeSH
• faktor C1 hostitelské buňky genetika   imunologie   MeSH
• heterozygot MeSH
• histony genetika   imunologie   MeSH
• kojenec MeSH
• lidé MeSH
• missense mutace * MeSH
• mladiství MeSH
• mutace ztráty funkce * MeSH
• nádorové supresorové proteiny nedostatek   genetika   imunologie   MeSH
• neurovývojové poruchy genetika   imunologie   patologie   MeSH
• předškolní dítě MeSH
• proteasomový endopeptidasový komplex genetika   imunologie   MeSH
• protein BRCA1 genetika   imunologie   MeSH
• regulace genové exprese MeSH
• restrukturace chromatinu genetika   imunologie   MeSH
• rodina MeSH
• T-lymfocyty imunologie   patologie   MeSH
• thiolesterasa ubikvitinu nedostatek   genetika   imunologie   MeSH
• ubikvitin genetika   imunologie   MeSH
• ubikvitinace MeSH
• ubikvitinligasy genetika   imunologie   MeSH
• zárodečné mutace * MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH