RESUMEN
The PIP3/PI3K network is a central regulator of metabolism and is frequently activated in cancer, commonly by loss of the PIP3/PI(3,4)P2 phosphatase, PTEN. Despite huge research investment, the drivers of the PI3K network in normal tissues and how they adapt to overactivation are unclear. We find that in healthy mouse prostate PI3K activity is driven by RTK/IRS signaling and constrained by pathway feedback. In the absence of PTEN, the network is dramatically remodeled. A poorly understood YXXM- and PIP3/PI(3,4)P2-binding PH domain-containing adaptor, PLEKHS1, became the dominant activator and was required to sustain PIP3, AKT phosphorylation, and growth in PTEN-null prostate. This was because PLEKHS1 evaded pathway-feedback and experienced enhanced PI3K- and Src-family kinase-dependent phosphorylation of Y258XXM, eliciting PI3K activation. hPLEKHS1 mRNA and activating Y419 phosphorylation of hSrc correlated with PI3K pathway activity in human prostate cancers. We propose that in PTEN-null cells receptor-independent, Src-dependent tyrosine phosphorylation of PLEKHS1 creates positive feedback that escapes homeostasis, drives PIP3 signaling, and supports tumor progression.
Asunto(s)
Fosfohidrolasa PTEN , Neoplasias de la Próstata , Animales , Humanos , Masculino , Ratones , Homeostasis , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Próstata/patología , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismoRESUMEN
INTRODUCTION: Skeletal muscles are characterized by their unique ability to regenerate. Injury of a so-called fast-twitch muscle, extensor digitorum longus (EDL), results in efficient regeneration and reconstruction of the functional tissue. In contrast, slow-twitch muscle (soleus) fails to properly reconstruct and develops fibrosis. This study focuses on soleus and EDL muscle regeneration and associated inflammation. METHODS: We determined differences in the activity of neutrophils and M1 and M2 macrophages using flow cytometry and differences in the levels of proinflammatory cytokines using Western blotting and immunolocalization at different times after muscle injury. RESULTS: Soleus muscle repair is accompanied by increased and prolonged inflammation, as compared to EDL. The proinflammatory cytokine profile is different in the soleus and ED muscles. CONCLUSIONS: Muscle repair efficiency differs by muscle fiber type. The inflammatory response affects the repair efficiency of slow- and fast-twitch muscles. Muscle Nerve 55: 400-409, 2017.
Asunto(s)
Inflamación/etiología , Fibras Musculares de Contracción Rápida/fisiología , Fibras Musculares de Contracción Lenta/fisiología , Regeneración/fisiología , Acetiltransferasas/metabolismo , Animales , Citocinas/metabolismo , Citometría de Flujo , Laminina/metabolismo , Macrófagos/metabolismo , Masculino , Enfermedades Musculares/complicaciones , Cadenas Pesadas de Miosina/metabolismo , Neutrófilos/metabolismo , Neutrófilos/patología , Ratas , Factores de Tiempo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
E-type cyclins (cyclins E1 and E2) are components of the cell cycle machinery that has been conserved from yeast to humans. The major function of E-type cyclins is to drive cell division. It is unknown whether in addition to their 'core' cell cycle functions, E-type cyclins also perform unique tissue-specific roles. Here, we applied high-throughput mass spectrometric analyses of mouse organs to define the repertoire of cyclin E protein partners in vivo. We found that cyclin E interacts with distinct sets of proteins in different compartments. These cyclin E interactors are highly enriched for phosphorylation targets of cyclin E and its catalytic partner, the cyclin-dependent kinase 2 (Cdk2). Among cyclin E interactors we identified several novel tissue-specific substrates of cyclin E-Cdk2 kinase. In proliferating compartments, cyclin E-Cdk2 phosphorylates Lin proteins within the DREAM complex. In the testes, cyclin E-Cdk2 phosphorylates Mybl1 and Dmrtc2, two meiotic transcription factors that represent key regulators of spermatogenesis. In embryonic and adult brains cyclin E interacts with proteins involved in neurogenesis, while in adult brains also with proteins regulating microtubule-based processes and microtubule cytoskeleton. We also used quantitative proteomics to demonstrate re-wiring of the cyclin E interactome upon ablation of Cdk2. This approach can be used to study how protein interactome changes during development or in any pathological state such as aging or cancer.
Asunto(s)
Ciclina E/genética , Quinasa 2 Dependiente de la Ciclina/genética , Ciclinas/genética , Proteínas Oncogénicas/genética , Proteómica , Animales , Ciclo Celular/genética , Proliferación Celular/genética , Ciclina E/metabolismo , Quinasa 2 Dependiente de la Ciclina/metabolismo , Ciclinas/metabolismo , Humanos , Masculino , Ratones , Proteínas Oncogénicas/metabolismo , Fosforilación , Mapas de Interacción de Proteínas/genética , Fase S/genética , Espermatogénesis/genética , Testículo/metabolismoRESUMEN
Matrix metalloproteinase (MMP) are a large family of enzymes, active in both physiological and pathological processes of many tissues. These proteases are able to selectively degrade components of the Extracellular Matrix (ECM). In skeletal muscle enzymes included in the MMP family are involved in tissue remodeling process, playing a key role in myogenesis as well as in tissue remodeling and regeneration of muscle. This paper describes the role of this group of enzymes in the conversion of skeletal muscle extracellular environment both in physiological processes in skeletal muscle and in the context of regeneration of the tissue.
