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Full-Text Articles in Medicine and Health Sciences
Regulation Of Cellular Protein Phosphatase-1 (Pp1) By Phosphorylation Of The Cpi-17 Family, C-Kinase-Activated Pp1 Inhibitors., Masumi Eto
Department of Molecular Physiology and Biophysics Faculty Papers
The regulatory circuit controlling cellular protein phosphatase-1 (PP1), an abundant group of Ser/Thr phosphatases, involves phosphorylation of PP1-specific inhibitor proteins. Malfunctions of these inhibitor proteins have been linked to a variety of diseases, including cardiovascular disease and cancer. Upon phosphorylation at Thr(38), the 17-kDa PP1 inhibitor protein, CPI-17, selectively inhibits a specific form of PP1, myosin light chain phosphatase, which transduces multiple kinase signals into the phosphorylation of myosin II and other proteins. Here, the mechanisms underlying PP1 inhibition and the kinase/PP1 cross-talk mediated by CPI-17 and its related proteins, PHI, KEPI, and GBPI, are discussed.
Solution Structure Of The Inhibitory Phosphorylation Domain Of Myosin Phosphatase Targeting Subunit 1., Shunsuke Mori, Ryou Iwaoka, Masumi Eto, Shin-Ya Ohki
Solution Structure Of The Inhibitory Phosphorylation Domain Of Myosin Phosphatase Targeting Subunit 1., Shunsuke Mori, Ryou Iwaoka, Masumi Eto, Shin-Ya Ohki
Department of Molecular Physiology and Biophysics Faculty Papers
Cell motility, such as smooth muscle contraction and cell migration, is controlled by the reversible phosphorylation of the regulatory light chain of myosin II and other cytoskeletal proteins. Mounting evidence suggests that in smooth muscle cells and other types of cells in vertebrates, myosin phosphatase (MP) plays an important role in controlling the phosphorylation of myosin II as well as other cytoskeletal proteins, including ezrin, moesin, and radixin.1 MP is a holoenzyme consisting of a catalytic subunit of a type-1 Ser/Thr phosphatase (PP1C) delta isoform, a myosin phosphatase targeting subunit 1 (MYPT1), and an accessory subunit M21. In this ternary …
Cardioprotective Effect Of Adiponectin Is Partially Mediated By Its Ampk-Independent Antinitrative Action., Yajing Wang, Ling Tao, Yuexing Yuan, Wayne Bond Lau, Rong Li, Bernard L. Lopez, Theodore A. Christopher, Rong Tian, Xin-Liang Ma
Cardioprotective Effect Of Adiponectin Is Partially Mediated By Its Ampk-Independent Antinitrative Action., Yajing Wang, Ling Tao, Yuexing Yuan, Wayne Bond Lau, Rong Li, Bernard L. Lopez, Theodore A. Christopher, Rong Tian, Xin-Liang Ma
Department of Emergency Medicine Faculty Papers
Adiponectin (APN) exerts its metabolic regulation largely through AMP-dependent protein kinase (AMPK). However, the role of AMPK in APN's antiapoptotic effect in ischemic-reperfused (I/R) adult cardiomyocytes remains incompletely understood. The present study was designed to determine the involvement of AMPK in the antiapoptotic signaling of APN. Cardiomyocytes from adult male mice overexpressing a dominant-negative alpha(2)-subunit of AMPK (AMPK-DN) or wild-type (WT) littermates were subjected to simulated I/R (SI/R) and pretreated with 2 microg/ml globular domain of APN (gAPN) or vehicle. SI/R-induced cardiomyocyte apoptosis was modestly increased in AMPK-DN cardiomyocytes (P < 0.05). Treatment with gAPN significantly reduced SI/R-induced apoptosis in WT cardiomyocytes as well as in AMPK-DN cardiomyocytes, indicating that the antiapoptotic effect of gAPN is partially AMPK independent. Furthermore, gAPN-induced endothelial nitric oxide synthase (eNOS) phosphorylation was significantly reduced in AMPK-DN cardiomyocytes, suggesting that the APN-eNOS signaling axis is impaired in AMPK-DN cardiomyocytes. Additional experiments demonstrated that treatment of AMPK-DN cardiomyocytes with gAPN reduced SI/R-induced NADPH oxidase overexpression, decreased superoxide generation, and blocked peroxynitrite formation to the same extent as that observed in WT cardiomyocytes. Collectively, our present study demonstrated that although the metabolic and eNOS activation effect of APN is largely mediated by AMPK, the superoxide-suppressing effect of APN is not mediated by AMPK, and this AMPK-independent antioxidant property of APN increased nitric oxide bioavailability and exerted significant antiapoptotic effect.
Systems-Level Interactions Between Insulin-Egf Networks Amplify Mitogenic Signaling., Nikolay Borisov, Edita Aksamitiene, Anatoly Kiyatkin, Stefan Legewie, Jan Berkhout, Thomas Maiwald, Nikolai P Kaimachnikov, Jens Timmer, Jan B Hoek, Boris N Kholodenko
Systems-Level Interactions Between Insulin-Egf Networks Amplify Mitogenic Signaling., Nikolay Borisov, Edita Aksamitiene, Anatoly Kiyatkin, Stefan Legewie, Jan Berkhout, Thomas Maiwald, Nikolai P Kaimachnikov, Jens Timmer, Jan B Hoek, Boris N Kholodenko
Department of Pathology, Anatomy, and Cell Biology Faculty Papers
Crosstalk mechanisms have not been studied as thoroughly as individual signaling pathways. We exploit experimental and computational approaches to reveal how a concordant interplay between the insulin and epidermal growth factor (EGF) signaling networks can potentiate mitogenic signaling. In HEK293 cells, insulin is a poor activator of the Ras/ERK (extracellular signal-regulated kinase) cascade, yet it enhances ERK activation by low EGF doses. We find that major crosstalk mechanisms that amplify ERK signaling are localized upstream of Ras and at the Ras/Raf level. Computational modeling unveils how critical network nodes, the adaptor proteins GAB1 and insulin receptor substrate (IRS), Src kinase, …
Elongation Factor 1 Alpha Interacts With Phospho-Akt In Breast Cancer Cells And Regulates Their Proliferation, Survival And Motility., Luisa Pecorari, Oriano Marin, Chiara Silvestri, Olivia Candini, Elena Rossi, Clara Guerzoni, Sara Cattelani, Samanta A Mariani, Francesca Corradini, Giovanna Ferrari-Amorotti, Laura Cortesi, Rita Bussolari, Giuseppe Raschellà, Massimo R Federico, Bruno Calabretta
Elongation Factor 1 Alpha Interacts With Phospho-Akt In Breast Cancer Cells And Regulates Their Proliferation, Survival And Motility., Luisa Pecorari, Oriano Marin, Chiara Silvestri, Olivia Candini, Elena Rossi, Clara Guerzoni, Sara Cattelani, Samanta A Mariani, Francesca Corradini, Giovanna Ferrari-Amorotti, Laura Cortesi, Rita Bussolari, Giuseppe Raschellà, Massimo R Federico, Bruno Calabretta
Kimmel Cancer Center Faculty Papers
BACKGROUND: Akt/PKB is a serine/threonine kinase that has attracted much attention because of its central role in regulating cell proliferation, survival, motility and angiogenesis. Activation of Akt in breast cancer portends aggressive tumour behaviour, resistance to hormone-, chemo-, and radiotherapy-induced apoptosis and it is correlated with decreased overall survival. Recent studies have identified novel tumor-specific substrates of Akt that may provide new diagnostic and prognostic markers and serve as therapeutic targets. This study was undertaken to identify pAkt-interacting proteins and to assess their biological roles in breast cancer cells. RESULTS: We confirmed that one of the pAkt interacting proteins is …