Life Sciences Commons^™

Mtorc2 Is Required For Rit-Mediated Oxidative Stress Resistance, Weikang Cai, Douglas A. Andres

Molecular and Cellular Biochemistry Faculty Publications

Rit, a member of the Ras family of GTPases, has been shown to promote cell survival in response to oxidative stress, in part by directing an evolutionarily conserved p38 MAPK-Akt survival cascade. Aberrant Rit signaling has recently been implicated as a driver mutation in human cancer, adding importance to the characterization of critical Rit effector pathways. However, the mechanism by which Rit-p38 signaling regulated Akt activity was unknown. Here, we identify mTORC2 as a critical downstream mediator of Rit-dependent survival signaling in response to reactive oxygen species (ROS) stress. Rit interacts with Sin1 (MAPKAP1), and Rit loss compromises ROS-dependent mTORC2 …

Arrhythmogenic Calmodulin Mutations Disrupt Intracellular Cardiomyocyte Ca2+ Regulation By Distinct Mechanisms, Guo Yin, Faisal Hassan, Ayman R. Haroun, Lisa L. Murphy, Lia Crotti, Peter J. Schwartz, Alfred L. George, Jonathan Satin

Physiology Faculty Publications

BACKGROUND: Calmodulin (CaM) mutations have been identified recently in subjects with congenital long QT syndrome (LQTS) or catecholaminergic polymorphic ventricular tachycardia (CPVT), but the mechanisms responsible for these divergent arrhythmia-susceptibility syndromes in this context are unknown. We tested the hypothesis that LQTS-associated CaM mutants disrupt Ca²⁺ homeostasis in developing cardiomyocytes possibly by affecting either late Na current or Ca²⁺-dependent inactivation of L-type Ca²⁺ current.

METHODS AND RESULTS: We coexpressed CaM mutants with the human cardiac Na channel (Na_V1.5) in tsA201 cells, and we used mammalian fetal ventricular cardiomyocytes to investigate LQTS- and CPVT-associated CaM …

Sudemycin E Influences Alternative Splicing And Changes Chromatin Modifications, Paolo Convertini, Manli Shen, Philip M. Potter, Gustavo Palacios, Chandraiah Lagisetti, Pierre De La Grange, Craig Horbinski, Yvonne N. Fondufe-Mittendorf, Thomas R. Webb, Stefan Stamm

Molecular and Cellular Biochemistry Faculty Publications

Sudemycin E is an analog of the pre-messenger RNA splicing modulator FR901464 and its derivative spliceostatin A. Sudemycin E causes the death of cancer cells through an unknown mechanism. We found that similar to spliceostatin A, sudemycin E binds to the U2 small nuclear ribonucleoprotein (snRNP) component SF3B1. Native chromatin immunoprecipitations showed that U2 snRNPs physically interact with nucleosomes. Sudemycin E induces a dissociation of the U2 snRNPs and decreases their interaction with nucleosomes. To determine the effect on gene expression, we performed genome-wide array analysis. Sudemycin E first causes a rapid change in alternative pre-messenger RNA splicing, which is …