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1.
J Biol Chem ; 294(3): 783-793, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30459234

RESUMO

SspH/IpaH bacterial effector E3 ubiquitin (Ub) ligases, unrelated in sequence or structure to eukaryotic E3s, are utilized by a wide variety of Gram-negative bacteria during pathogenesis. These E3s function in a eukaryotic environment, utilize host cell E2 ubiquitin-conjugating enzymes of the Ube2D family, and target host proteins for ubiquitylation. Despite several crystal structures, details of Ube2D∼Ub binding and the mechanism of ubiquitin transfer are poorly understood. Here, we show that the catalytic E3 ligase domain of SspH1 can be divided into two subdomains: an N-terminal subdomain that harbors the active-site cysteine and a C-terminal subdomain containing the Ube2D∼Ub-binding site. SspH1 mutations designed to restrict subdomain motions show rapid formation of an E3∼Ub intermediate, but impaired Ub transfer to substrate. NMR experiments using paramagnetic spin labels reveal how SspH1 binds Ube2D∼Ub and targets the E2∼Ub active site. Unexpectedly, hydrogen/deuterium exchange MS shows that the E2∼Ub-binding region is dynamic but stabilized in the E3∼Ub intermediate. Our results support a model in which both subunits of an Ube2D∼Ub clamp onto a dynamic region of SspH1, promoting an E3 conformation poised for transthiolation. A conformational change is then required for Ub transfer from E3∼Ub to substrate.


Assuntos
Proteínas de Bactérias/química , Salmonella/enzimologia , Ubiquitina-Proteína Ligases/química , Ubiquitinação , Substituição de Aminoácidos , Proteínas de Bactérias/genética , Catálise , Mutação de Sentido Incorreto , Domínios Proteicos , Salmonella/genética , Ubiquitina-Proteína Ligases/genética
2.
Cancer Discov ; 13(3): 580-597, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36416874

RESUMO

To address antigen escape and loss of T-cell functionality, we report a phase I clinical trial (NCT04007029) evaluating autologous naive and memory T (TN/MEM) cells engineered to express a bispecific anti-CD19/CD20 chimeric antigen receptor (CAR; CART19/20) for patients with relapsed/refractory non-Hodgkin lymphoma (NHL), with safety as the primary endpoint. Ten patients were treated with 36 × 106 to 165 × 106 CART19/20 cells. No patient experienced neurotoxicity of any grade or over grade 1 cytokine release syndrome. One case of dose-limiting toxicity (persistent cytopenia) was observed. Nine of 10 patients achieved objective response [90% overall response rate (ORR)], with seven achieving complete remission [70% complete responses (CR) rate]. One patient relapsed after 18 months in CR but returned to CR after receiving a second dose of CART19/20 cells. Median progression-free survival was 18 months and median overall survival was not reached with a 17-month median follow-up. In conclusion, CART19/20 TN/MEM cells are safe and effective in patients with relapsed/refractory NHL, with durable responses achieved at low dosage levels. SIGNIFICANCE: Autologous CD19/CD20 bispecific CAR-T cell therapy generated from TN/MEM cells for patients with NHL is safe (no neurotoxicity, maximum grade 1 cytokine release syndrome) and demonstrates strong efficacy (90% ORR, 70% CR rate) in a first-in-human, phase I dose-escalation trial. This article is highlighted in the In This Issue feature, p. 517.


Assuntos
Linfoma não Hodgkin , Receptores de Antígenos Quiméricos , Humanos , Receptores de Antígenos Quiméricos/genética , Síndrome da Liberação de Citocina/etiologia , Síndrome da Liberação de Citocina/terapia , Células T de Memória , Linfoma não Hodgkin/terapia , Imunoterapia Adotiva/efeitos adversos , Antígenos CD19
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