RESUMO
Rare mutations in CARD14 promote psoriasis by inducing CARD14-BCL10-MALT1 complexes that activate NF-κB and MAP kinases. Here, the downstream signalling mechanism of the highly penetrant CARD14E138A alteration is described. In addition to BCL10 and MALT1, CARD14E138A associated with several proteins important in innate immune signalling. Interactions with M1-specific ubiquitin E3 ligase HOIP, and K63-specific ubiquitin E3 ligase TRAF6 promoted BCL10 ubiquitination and were essential for NF-κB and MAP kinase activation. In contrast, the ubiquitin binding proteins A20 and ABIN1, both genetically associated with psoriasis development, negatively regulated signalling by inducing CARD14E138A turnover. CARD14E138A localized to early endosomes and was associated with the AP2 adaptor complex. AP2 function was required for CARD14E138A activation of mTOR complex 1 (mTORC1), which stimulated keratinocyte metabolism, but not for NF-κB nor MAP kinase activation. Furthermore, rapamycin ameliorated CARD14E138A-induced keratinocyte proliferation and epidermal acanthosis in mice, suggesting that blocking mTORC1 may be therapeutically beneficial in CARD14-dependent psoriasis.
Assuntos
Proteínas Adaptadoras de Sinalização CARD , Proliferação de Células , Endossomos , Queratinócitos , Alvo Mecanístico do Complexo 1 de Rapamicina , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Humanos , Animais , Queratinócitos/metabolismo , Camundongos , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas Adaptadoras de Sinalização CARD/genética , Endossomos/metabolismo , Transdução de Sinais , Psoríase/metabolismo , Psoríase/patologia , Psoríase/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , NF-kappa B/metabolismo , NF-kappa B/genética , Proteína 10 de Linfoma CCL de Células B/metabolismo , Proteína 10 de Linfoma CCL de Células B/genética , Ubiquitinação , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Fator 6 Associado a Receptor de TNF/metabolismo , Fator 6 Associado a Receptor de TNF/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Células HEK293 , Transporte Proteico , Guanilato CiclaseRESUMO
Inherited and de novo mutations in the CARD14 gene promote the development of psoriasis, an inflammatory disease of the skin. Caspase recruitment domain-containing protein 14 (CARD14) is a member of the CARMA protein family that includes the structurally related CARD11 adaptor that mediates NF-κB activation by antigen receptors. We investigated the mechanism by which CARD14 mutation in psoriasis activates NF-κB. In contrast with wild-type CARD14, CARD14(E138A) and CARD14(G117S) psoriasis mutants interacted constitutively with BCL10 and MALT1, and triggered BCL10- and MALT1-dependent activation of NF-κB in keratinocytes. These alterations disrupted the inhibitory effect of the CARD14 linker region (LR) on NF-κB activation by facilitating BCL10 binding. Therefore, psoriasis mutations activated CARD14 by a mechanism analogous to oncogenic CARD11 mutations in non-Hodgkin B cell lymphomas. CARD14(E138A) also stimulated MALT1 paracaspase activity and activated both ERK1/2 and p38α MAP kinases. Inhibition of MALT1 with mepazine reduced CARD14(E138A)-induced expression of specific psoriasis-associated transcripts in keratinocytes. Our results establish the mechanism whereby gain-of-function CARD14 variants, which induce psoriatic disease in affected individuals, activate pro-inflammatory signalling.