Project description:The p21 RAS subfamily of small GTPases, including KRAS, HRAS, and NRAS, regulates cell proliferation, cytoskeletal organization and other signaling networks, and is the most frequent target of activating mutations in cancer. Activating germline mutations of KRAS and HRAS cause severe developmental abnormalities leading to Noonan, cardio-facial-cutaneous and Costello syndrome, but activating germline mutations of NRAS have not been reported. Autoimmune lymphoproliferative syndrome (ALPS) is the most common genetic disease of lymphocyte apoptosis and causes autoimmunity as well as excessive lymphocyte accumulation, particularly of CD4-, CD8- ab T cells. Mutations in ALPS typically affect CD95 (Fas/APO-1)-mediated apoptosis, one of the extrinsic death pathways involving tumor necrosis factor receptor (TNFR) superfamily proteins, but certain ALPS individuals have no such mutations. We show here that the salient features of ALPS as well as a predisposition to hematological malignancies can be caused by a heterozygous germline Gly13Asp activating mutation of the NRAS oncogene that does not impair CD95-mediated apoptosis. The increase in active, GTP-bound NRAS augments RAF/MEK/ERK signaling which markedly decreases the pro-apoptotic protein BIM and attenuates intrinsic, nonreceptor-mediated mitochondrial apoptosis. Thus, germline activating mutations in NRAS differ from other p21 Ras oncoproteins by causing selective immune abnormalities without general developmental defects. Our observations on the effects of NRAS activation indicate that RAS-inactivating drugs, such as farnesyl-transferase inhibitors (FTIs) should be examined in human autoimmune and lymphocyte homeostasis disorders. Experiment Overall Design: Describes the discovery of a new gene underlying a novel type of autoimmune lymphoproliferative syndrome, and characterizes the mechanisms involved in the pathogenesis of the disease.
Project description:PRKAR1A inactivating mutations are responsible for primary pigmented nodular adrenocortical disease (PPNAD) whereas somatic GNAS activating mutations cause macronodular disease in the context of McCune-Albright syndrome (MAS), ACTH-independent hyperplasia (AIMAH) and, rarely, cortisol-producing adenomas (CPA). The whole-genome expression profile (WGEP) of normal (pooled) adrenals, PRKAR1A- (3) and GNAS-mutant (3) was studied. Total RNA obtained from adrenal tumors were compared to those samples obtained from normal adrenal pools
Project description:PRKAR1A inactivating mutations are responsible for primary pigmented nodular adrenocortical disease (PPNAD) whereas somatic GNAS activating mutations cause macronodular disease in the context of McCune-Albright syndrome (MAS), ACTH-independent hyperplasia (AIMAH) and, rarely, cortisol-producing adenomas (CPA). The whole-genome expression profile (WGEP) of normal (pooled) adrenals, PRKAR1A- (3) and GNAS-mutant (3) was studied.
Project description:UBA1 initiates most cellular ubiquitin signaling by activating and transferring ubiquitin to tens of E2 enzymes. Clonally acquired UBA1 missense mutations cause a severe inflammatory-hematologic overlap disease called VEXAS (vacuoles, E1, X-linked autoinflammatory, somatic) syndrome. Despite extensive investigation into the clinical manifestations of this lethal disease, little is known about the underlying molecular mechanisms. Here, we systematically dissect VEXAS-causing mutations in UBA1 to better understand disease pathogenesis. We find that only UBA1 p.Met41 mutations alter cytoplasmic isoform expression, while the remaining mutations reduce catalytic function of both cytoplasmic and nuclear isoforms by diverse mechanisms, including defective ubiquitin adenylation, reduced thioesterification, and aberrant oxyester formation. Strikingly, most non-p.Met41 mutations prominently affect transthioesterification, revealing ubiquitin conjugation to cytoplasmic E2 enzymes as a shared property of pathogenesis amongst different VEXAS syndrome genotypes.
Project description:The p21 RAS subfamily of small GTPases, including KRAS, HRAS, and NRAS, regulates cell proliferation, cytoskeletal organization and other signaling networks, and is the most frequent target of activating mutations in cancer. Activating germline mutations of KRAS and HRAS cause severe developmental abnormalities leading to Noonan, cardio-facial-cutaneous and Costello syndrome, but activating germline mutations of NRAS have not been reported. Autoimmune lymphoproliferative syndrome (ALPS) is the most common genetic disease of lymphocyte apoptosis and causes autoimmunity as well as excessive lymphocyte accumulation, particularly of CD4-, CD8- ab T cells. Mutations in ALPS typically affect CD95 (Fas/APO-1)-mediated apoptosis, one of the extrinsic death pathways involving tumor necrosis factor receptor (TNFR) superfamily proteins, but certain ALPS individuals have no such mutations. We show here that the salient features of ALPS as well as a predisposition to hematological malignancies can be caused by a heterozygous germline Gly13Asp activating mutation of the NRAS oncogene that does not impair CD95-mediated apoptosis. The increase in active, GTP-bound NRAS augments RAF/MEK/ERK signaling which markedly decreases the pro-apoptotic protein BIM and attenuates intrinsic, nonreceptor-mediated mitochondrial apoptosis. Thus, germline activating mutations in NRAS differ from other p21 Ras oncoproteins by causing selective immune abnormalities without general developmental defects. Our observations on the effects of NRAS activation indicate that RAS-inactivating drugs, such as farnesyl-transferase inhibitors (FTIs) should be examined in human autoimmune and lymphocyte homeostasis disorders. Keywords: NRAS
Project description:IKKα, encoded by CHUK, is crucial in the non-canonical NF-κB pathway and part of the IKK complex activating the canonical pathway alongside IKKβ. Absence of IKKα cause fetal encasement syndrome in human, fatal in utero, while an impaired IKKα-NIK interaction was reported in a single patient and cause combined immunodeficiency. Here, we describe compound heterozygous variants in the kinase domain of IKKα in a female patient with hypogammaglobulinemia, recurrent lung infections, and Hay-Wells syndrome-like features. We showed that both variants were kinase dead mutants. Non-canonical NF-κB activation was abolished in stromal and immune cells while the canonical pathway was partially impaired. Reintroducing wild-type CHUK restored non-canonical NF-κB activation. The patient had neutralizing autoantibodies against type I IFN, akin to non-canonical NF-κB pathway deficiencies. Thus, this is the first case of bi-allelic CHUK mutations disrupting IKKα kinase function, broadening non-canonical NF-κB defect understanding and suggesting IKKα's role in both NF-κB pathways.
2024-11-24 | GSE267600 | GEO
Project description:Potential mutations that cause ARVC