Akt-dependent Activation of mTORC1 Complex Involves Phosphorylation of mTOR (Mammalian Target of Rapamycin) by IκB Kinase α (IKKα)

The serine/threonine protein kinase Akt promotes cell survival, growth, and proliferation through phosphorylation of different downstream substrates. A key effector of Akt is the mammalian target of rapamycin (mTOR). Akt is known to stimulate mTORC1 activity through phosphorylation of tuberous sclerosis complex 2 (TSC2) and PRAS40, both negative regulators of mTOR activity. We previously reported that IκB kinase α (IKKα), a component of the kinase complex that leads to NF-κB activation, plays an important role in promoting mTORC1 activity downstream of activated Akt. Here, we demonstrate IKKα-dependent regulation of mTORC1 using multiple PTEN null cancer cell lines and an animal model with deletion of IKKα. Importantly, IKKα is shown to phosphorylate mTOR at serine 1415 in a manner dependent on Akt to promote mTORC1 activity. These results demonstrate that IKKα is an effector of Akt in promoting mTORC1 activity

Akt-dependent Activation of mTORC1 Complex Involves Phosphorylation of mTOR (Mammalian Target of Rapamycin) by I kappa B Kinase alpha (IKK alpha)

The serine/threonine protein kinase Akt promotes cell survival, growth, and proliferation through phosphorylation of different downstream substrates. A key effector of Akt is the mammalian target of rapamycin (mTOR). Akt is known to stimulate mTORC1 activity through phosphorylation of tuberous sclerosis complex 2 (TSC2) and PRAS40, both negative regulators of mTOR activity. We previously reported that I kappa B kinase alpha (IKK alpha), a component of the kinase complex that leads to NF-kappa B activation, plays an important role in promoting mTORC1 activity downstream of activated Akt. Here, we demonstrate IKK alpha-dependent regulation of mTORC1 using multiple PTEN null cancer cell lines and an animal model with deletion of IKK alpha. Importantly, IKK alpha is shown to phosphorylate mTOR at serine 1415 in a manner dependent on Akt to promote mTORC1 activity. These results demonstrate that IKK alpha is an effector of Akt in promoting mTORC1 activity

Mutation analysis of the HFE gene in brazilian populations

Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.Universidade de Campinas. Faculdade de Ciências Médicas. Hemocentro and Departamento de Clínica Médica. São Paulo, SP, Brasil.We analyzed the frequency of the C282Y and H63D mutations in the HFE gene in 227 individuals from Brazil comprising 71 Caucasians, 91 racially mixed Caucasian African-derived Amerindians (both populations from Southeast Brazil), 85 African-derived subjects (from Northeast Brazil) and 75 Parakanã Indians. Allelic frequency of the mutation C. 845G6A (C282Y) was 1.4% in the Caucasian population, 1.1% in the African-derived population, 1.1% in the racially mixed normal controls and 0% in the Parakanã Indians. In the African-derived population, the C282Y mutation was present on chromosomes bearing the haplotype 6/1h according to Beutler and West (1997). Allelic frequency of the mutation C. 187C6G (H63D) was 16.3% in the Caucasian population, 7.5% in the African-derived population, 9.8% in the racially mixed controls and 0% in the Amerindians. The presence of these mutations in the African-derived population reflects the fact that these subjects may have undergone a non-identified racial admixture in their past history. The absence of both defects in the Amerindians suggests that these mutations have emerged after the migration of Polynesians to America, or that they may not have reached the Polynesian population until after the migration to America had occurred