Medicine and Health Sciences Commons^™

Gasdermins In Apoptosis: New Players In An Old Game., Corey Rogers, Emad S. Alnemri

Department of Biochemistry and Molecular Biology Faculty Papers

Apoptosis is a form of programmed cell death (PCD) that plays critical physiological roles in removing superfluous or dangerous cell populations that are unneeded or threatening to the health of the host organism. Although the molecular pathways leading to activation of the apoptotic program have been extensively studied and characterized starting in the 1970s, new evidence suggests that members of the gasdermin superfamily are novel pore-forming proteins that augment apoptosis by permeabilizing the mitochondria and participate in the final stages of the apoptotic program by inducing secondary necrosis/pyroptosis. These findings may explain outstanding questions in the field such as why …

Multiple Mitochondrial Thioesterases Have Distinct Tissue And Substrate Specificity And Coa Regulation, Suggesting Unique Functional Roles., Carmen Bekeova, Lauren Anderson-Pullinger, Kevin Boye, Felix Boos, Yana Sharpadskaya, Johannes M Herrmann, Erin L. Seifert

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Acyl-CoA thioesterases (Acots) hydrolyze fatty acyl-CoA esters. Acots in the mitochondrial matrix are poised to mitigate β-oxidation overload and maintain CoA availability. Several Acots associate with mitochondria, but whether they all localize to the matrix, are redundant, or have different roles is unresolved. Here, we compared the suborganellar localization, activity, expression, and regulation among mitochondrial Acots (Acot2, -7, -9, and -13) in mitochondria from multiple mouse tissues and from a model of Acot2 depletion. Acot7, -9, and -13 localized to the matrix, joining Acot2 that was previously shown to localize there. Mitochondria from heart, skeletal muscle, brown adipose tissue, and …

Dysregulation Of Mitochondrial Ca2+ Uptake And Sarcolemma Repair Underlie Muscle Weakness And Wasting In Patients And Mice Lacking Micu1, Valentina Debattisti, Adam Horn, Raghavendra Singh, Erin L. Seifert, Marshall W. Hogarth, Davi A. Mazala, Kai Ting Huang, Rita Horvath, Jyoti K. Jaiswal, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Muscle function is regulated by Ca²⁺, which mediates excitation-contraction coupling, energy metabolism, adaptation to exercise, and sarcolemmal repair. Several of these actions rely on Ca²⁺ delivery to the mitochondrial matrix via the mitochondrial Ca²⁺ uniporter, the pore of which is formed by mitochondrial calcium uniporter (MCU). MCU's gatekeeping and cooperative activation are controlled by MICU1. Loss-of-protein mutation in MICU1 causes a neuromuscular disease. To determine the mechanisms underlying the muscle impairments, we used MICU1 patient cells and skeletal muscle-specific MICU1 knockout mice. Both these models show a lower threshold for MCU-mediated Ca²⁺ uptake. Lack of …

Heat Shock Factor 1-Mediated Transcription Activation Of Omi/Htra2 Induces Myocardial Mitochondrial Apoptosis In The Aging Heart., Dan Liu, Linguo Wu, Ye Wu, Xin Wei, Wen Wang, Suli Zhang, Ming Yi, Jing Li, Huirong Liu, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

BACKGROUND: Increased cardiac apoptosis is a hallmark of the elderly, which in turn increases the risk for developing cardiac disease. The overexpression of Omi/HtrA2 mRNA and protein contributes to apoptosis in the aged heart. Heat shock factor 1 (HSF1) is a transcription factor that binds to the promoter of Omi/HtrA2 in the aging myocardium. However, whether HSF1 participates in cardiomyocyte apoptosis via transcriptional regulation of Omi/HtrA2 remains unclear. The present study was designed to investigate whether HSF1 plays a role in Omi/HtrA2 transcriptional regulation and myocardial apoptosis.

METHODS AND RESULTS: Assessment of the hearts of mice of different ages was …

Myc-Mediated Transcriptional Regulation Of The Mitochondrial Chaperone Trap1 Controls Primary And Metastatic Tumor Growth., Ekta Agarwal, Brian J. Altman, Jae Ho Seo, Jagadish C. Ghosh, Andrew V Kossenkov, Hsin-Yao Tang, Shiv Ram Krishn, Lucia R. Languino, Dmitry I. Gabrilovich, David W. Speicher, Chi V. Dang, Dario C. Altieri

Department of Cancer Biology Faculty Papers

The role of mitochondria in cancer continues to be debated, and whether exploitation of mitochondrial functions is a general hallmark of malignancy or a tumor- or context-specific response is still unknown. Using a variety of cancer cell lines and several technical approaches, including siRNA-mediated gene silencing, ChIP assays, global metabolomics and focused metabolite analyses, bioenergetics, and cell viability assays, we show that two oncogenic Myc proteins, c-Myc and N-Myc, transcriptionally control the expression of the mitochondrial chaperone TNFR-associated protein- 1 (TRAP1) in cancer. In turn, this Myc-mediated regulation preserved the folding and function of mitochondrial oxidative phosphorylation (OXPHOS) complex II …

Yeast Mitochondrial Protein Pet111p Binds Directly To Two Distinct Targets In Cox2 Mrna, Suggesting A Mechanism Of Translational Activation, Julia L Jones, Katharina B. Hofmann, Andrew T. Cowan, Dmitry Temiakov, Patrick Cramer, Michael Anikin

Department of Biochemistry and Molecular Biology Faculty Papers

The genes in mitochondrial DNA code for essential subunits of the respiratory chain complexes. In yeast, expression of mitochondrial genes is controlled by a group of gene-specific translational activators encoded in the nucleus. These factors appear to be part of a regulatory system that enables concerted expression of the necessary genes from both nuclear and mitochondrial genomes to produce functional respiratory complexes. Many of the translational activators are believed to act on the 5'-untranslated regions of target mRNAs, but the molecular mechanisms involved in this regulation remain obscure. In this study, we used a combination of in vivo and in …

Gasdermin Pores Permeabilize Mitochondria To Augment Caspase-3 Activation During Apoptosis And Inflammasome Activation., Corey Rogers, Dan A. Erkes, Alexandria Nardone, Andrew E. Aplin, Teresa Fernandes-Alnemri, Emad S. Alnemri

Department of Biochemistry and Molecular Biology Faculty Papers

Gasdermin E (GSDME/DFNA5) cleavage by caspase-3 liberates the GSDME-N domain, which mediates pyroptosis by forming pores in the plasma membrane. Here we show that GSDME-N also permeabilizes the mitochondrial membrane, releasing cytochrome c and activating the apoptosome. Cytochrome c release and caspase-3 activation in response to intrinsic and extrinsic apoptotic stimuli are significantly reduced in GSDME-deficient cells comparing with wild type cells. GSDME deficiency also accelerates cell growth in culture and in a mouse model of melanoma. Phosphomimetic mutation of the highly conserved phosphorylatable Thr6 residue of GSDME, inhibits its pore-forming activity, thus uncovering a potential mechanism by which GSDME …