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Full-Text Articles in Cell Biology

Expression Of Mitochondrial Membrane-Linked Sab Determines Severity Of Sex-Dependent Acute Liver Injury, Sanda Win, Robert W. M. Min, Christopher Q. Chen, Jun Zhang, Yibu Chen, Meng Li, Ayako Suzuki, Manal F. Abdelmalek, Ying Wang, Mariam Aghajan, Filbert W. M. Aung, Anna Mae Diehl, Roger J. Davis, Tin A. Than, Neil Kaplowitz Sep 2019

Expression Of Mitochondrial Membrane-Linked Sab Determines Severity Of Sex-Dependent Acute Liver Injury, Sanda Win, Robert W. M. Min, Christopher Q. Chen, Jun Zhang, Yibu Chen, Meng Li, Ayako Suzuki, Manal F. Abdelmalek, Ying Wang, Mariam Aghajan, Filbert W. M. Aung, Anna Mae Diehl, Roger J. Davis, Tin A. Than, Neil Kaplowitz

University of Massachusetts Medical School Faculty Publications

SAB is an outer membrane docking protein for JNK mediated impaired mitochondrial function. Deletion of Sab in hepatocytes inhibits sustained JNK activation and cell death. Current work demonstrated that increasing SAB enhanced the severity of APAP liver injury. Female mice were resistant to liver injury and exhibited markedly decreased hepatic SAB protein expression versus males. The mechanism of SAB repression involved a pathway from ERalpha to p53 expression which induced miR34a-5p. miR34a-5p targeted the Sab mRNA coding region, repressing SAB expression. Fulvestrant or p53 knockdown decreased miR34a-5p and increased SAB in females leading to increased injury from APAP and TNF ...


Distinct Features Of Nucleolus-Associated Domains In Mouse Embryonic Stem Cells, Aizhan Bizhanova, Aimin Yan, Jun Yu, Lihua Julie Zhu, Paul D. Kaufman Aug 2019

Distinct Features Of Nucleolus-Associated Domains In Mouse Embryonic Stem Cells, Aizhan Bizhanova, Aimin Yan, Jun Yu, Lihua Julie Zhu, Paul D. Kaufman

University of Massachusetts Medical School Faculty Publications

Background Heterochromatin in eukaryotic interphase cells frequently localizes to the nucleolar periphery (nucleolus-associated domains, NADs) and the nuclear lamina (lamina-associated domains, LADs). Gene expression in somatic cell NADs is generally low, but NADs have not been characterized in mammalian stem cells.

Results Here, we generated the first genome-wide map of NADs in mouse embryonic stem cells (mESCs) via deep sequencing of chromatin associated with biochemically-purified nucleoli. As we had observed in mouse embryonic fibroblasts (MEFs), the large Type I subset of NADs overlaps with constitutive LADs and is enriched for features of constitutive heterochromatin, including late replication timing and low ...


Leptin Promotes Expression Of Emt-Related Transcription Factors And Invasion In A Src And Fak-Dependent Pathway In Mcf10a Mammary Epithelial Cells, Monserrat Olea-Flores, Miriam Zuñiga-Eulogio, Arvey Tacuba-Saavedra, Magdalena Bueno-Salgado, Andrea Sánchez-Carvajal, Yovani Vargas-Santiago, Miguel A. Mendoza-Catalán, Eduardo Pérez Salazar, Alejandra García-Hernández, Teresita Padilla-Benavides, Napoleón Navarro-Tito Aug 2019

Leptin Promotes Expression Of Emt-Related Transcription Factors And Invasion In A Src And Fak-Dependent Pathway In Mcf10a Mammary Epithelial Cells, Monserrat Olea-Flores, Miriam Zuñiga-Eulogio, Arvey Tacuba-Saavedra, Magdalena Bueno-Salgado, Andrea Sánchez-Carvajal, Yovani Vargas-Santiago, Miguel A. Mendoza-Catalán, Eduardo Pérez Salazar, Alejandra García-Hernández, Teresita Padilla-Benavides, Napoleón Navarro-Tito

University of Massachusetts Medical School Faculty Publications

Leptin is one of the main adipokines secreted in breast tissue, and has been associated with epithelial-mesenchymal transition (EMT) and tumor progression in breast cancer. Leptin promotes EMT, cell migration and invasion in epithelial breast cells, leading to tumor progression. However, the molecular mechanism that underlies these events is not fully understood; however, the activation of different signaling pathways appears to be essential. In this sense, the effect of leptin on the activation of kinases like Src and FAK, which regulate signaling pathways that activate the EMT program, has not been completely described. Therefore, we investigated the involvement of these ...


Ste5 Membrane Localization Allows Mapk Pathway Signaling In Trans Between Kinases On Separate Scaffold Molecules, Rachel E. Lamson, Matthew J. Winters, Peter M. Pryciak Jun 2019

Ste5 Membrane Localization Allows Mapk Pathway Signaling In Trans Between Kinases On Separate Scaffold Molecules, Rachel E. Lamson, Matthew J. Winters, Peter M. Pryciak

University of Massachusetts Medical School Faculty Publications

The MAP kinase cascade is a ubiquitous eukaryotic signaling module that can be controlled by a diverse group of scaffold proteins. In budding yeast, activation of the mating MAP kinase cascade involves regulated membrane recruitment of the archetypal scaffold protein Ste5. This event promotes activation of the first kinase, but it also enhances subsequent signal propagation through the remainder of the cascade. By studying this latter effect, we find that membrane recruitment promotes signaling in trans between kinases on separate Ste5 molecules. First, trans signaling requires all Ste5 domains that mediate membrane recruitment, including both protein-binding and membrane-binding domains. Second ...


Mtf1, A Classic Metal Sensing Transcription Factor, Promotes Myogenesis In Response To Copper, Cristina Tavera-Montañez, Sarah J. Hainer, Daniella Cangussu, Shellaina J. V. Gordon, Yao Xiao, Pablo Reyes-Gutierrez, Anthony N. Imbalzano, Juan G. Navea, Thomas G. Fazzio, Teresita Padilla-Benavides Jun 2019

Mtf1, A Classic Metal Sensing Transcription Factor, Promotes Myogenesis In Response To Copper, Cristina Tavera-Montañez, Sarah J. Hainer, Daniella Cangussu, Shellaina J. V. Gordon, Yao Xiao, Pablo Reyes-Gutierrez, Anthony N. Imbalzano, Juan G. Navea, Thomas G. Fazzio, Teresita Padilla-Benavides

University of Massachusetts Medical School Faculty Publications

MTF1 is a conserved metal-binding transcription factor in eukaryotes that binds to conserved DNA sequence motifs, termed metal response elements (MREs). MTF1 responds to metal excess and deprivation, protects cells from oxidative and hypoxic stresses, and is required for embryonic development in vertebrates. We used multiple strategies to identify an unappreciated role for MTF1 and copper (Cu) in cell differentiation. Upon initiation of myogenesis from primary myoblasts, MTF1 expression increased, as did nuclear localization. Mtf1 knockdown impaired differentiation, while addition of non-toxic concentrations of Cu+ enhanced MTF1 expression and promoted myogenesis. Cu+ bound stoichiometrically to a C-terminus tetra-cysteine of MTF1 ...


Brg1 Is A Prognostic Indicator And A Potential Therapeutic Target For Prostate Cancer, Rohini Muthuswami, Leeann Bailey, Radhakrishnan Rakesh, Anthony N. Imbalzano, Jeffrey A. Nickerson, Joel W. Hockensmith Jan 2019

Brg1 Is A Prognostic Indicator And A Potential Therapeutic Target For Prostate Cancer, Rohini Muthuswami, Leeann Bailey, Radhakrishnan Rakesh, Anthony N. Imbalzano, Jeffrey A. Nickerson, Joel W. Hockensmith

University of Massachusetts Medical School Faculty Publications

Brahma-related gene 1 (BRG1) is one of two mutually exclusive ATPases that function as the catalytic subunit of human SWItch/Sucrose NonFermentable (SWI/SNF) chromatin remodeling enzymes. BRG1 has been identified as a tumor suppressor in some cancer types but has been shown to be expressed at elevated levels, relative to normal tissue, in other cancers. Using TCGA (The Cancer Genome Atlas) prostate cancer database, we determined that BRG1 mRNA and protein expression is elevated in prostate tumors relative to normal prostate tissue. Only 3 of 491 (0.6%) sequenced tumors showed amplification of the locus or mutation in the ...


Two Contrasting Classes Of Nucleolus-Associated Domains In Mouse Fibroblast Heterochromatin, Anastassiia Vertii, Jianhong Ou, Jun Yu, Aimin Yan, Hervé Pagès, Haibo Liu, Lihua Julie Zhu, Paul D. Kaufman Dec 2018

Two Contrasting Classes Of Nucleolus-Associated Domains In Mouse Fibroblast Heterochromatin, Anastassiia Vertii, Jianhong Ou, Jun Yu, Aimin Yan, Hervé Pagès, Haibo Liu, Lihua Julie Zhu, Paul D. Kaufman

University of Massachusetts Medical School Faculty Publications

In interphase eukaryotic cells, almost all heterochromatin is located adjacent to the nucleolus or to the nuclear lamina, thus defining Nucleolus Associated Domains (NADs) and Lamina Associated Domains (LADs), respectively. Here, we determined the first genome-scale map of murine NADs in mouse embryonic fibroblasts (MEFs) via deep sequencing of chromatin associated with purified nucleoli. We developed a Bioconductor package called NADfinder and demonstrated that it identifies NADs more accurately than other peak-calling tools, due to its critical feature of chromosome-level local baseline correction. We detected two distinct classes of NADs. Type I NADs associate frequently with both the nucleolar periphery ...


Identification Of A Novel Invasion-Promoting Region In Insulin Receptor Substrate 2, Jose Mercado-Matos, Jenny Janusis, Sha Zhu, Samuel S. Chen, Leslie M. Shaw Jun 2018

Identification Of A Novel Invasion-Promoting Region In Insulin Receptor Substrate 2, Jose Mercado-Matos, Jenny Janusis, Sha Zhu, Samuel S. Chen, Leslie M. Shaw

University of Massachusetts Medical School Faculty Publications

Although the insulin receptor substrate (IRS) proteins IRS1 and IRS2 share considerable homology and activate common signaling pathways, their contributions to breast cancer are distinct. IRS1 has been implicated in the proliferation and survival of breast tumor cells. In contrast, IRS2 facilitates glycolysis, invasion, and metastasis. To determine the mechanistic basis for IRS2-dependent functions, we investigated unique structural features of IRS2 that are required for invasion. Our studies revealed that the ability of IRS2 to promote invasion is dependent upon upstream insulin-like growth factor 1 receptor (IGF-1R)/insulin receptor (IR) activation and the recruitment and activation of phosphatidylinositol 3-kinase (PI3K ...


Nuclear Export Through Nuclear Envelope Remodeling In Saccharomyces Cerevisiae, Baojin Ding, Anne M. Mirza, James A. Ashley, Vivian Budnik, Mary Munson Jun 2018

Nuclear Export Through Nuclear Envelope Remodeling In Saccharomyces Cerevisiae, Baojin Ding, Anne M. Mirza, James A. Ashley, Vivian Budnik, Mary Munson

University of Massachusetts Medical School Faculty Publications

In eukaryotes, subsets of exported mRNAs are organized into large ribonucleoprotein (megaRNP) granules. How megaRNPs exit the nucleus is unclear, as their diameters are much larger than the nuclear pore complex (NPC) central channel. We previously identified a non-canonical nuclear export mechanism in Drosophila (Speese et al., Cell 2012) and mammals (Ding et al., in preparation), in which megaRNPs exit the nucleus by budding across nuclear envelope (NE) membranes. Here, we present evidence for a similar pathway in the nucleus of the budding yeast S. cerevisiae, which contain morphologically similar granules bearing mRNAs. Wild-type yeast displayed these granules at very ...


Cell Clustering Mediated By The Adhesion Protein Pvrl4 Is Necessary For Alpha6beta4 Integrin-Promoted Ferroptosis Resistance In Matrix-Detached Cells, Caitlin W. Brown, John J. Amante, Arthur M. Mercurio Jun 2018

Cell Clustering Mediated By The Adhesion Protein Pvrl4 Is Necessary For Alpha6beta4 Integrin-Promoted Ferroptosis Resistance In Matrix-Detached Cells, Caitlin W. Brown, John J. Amante, Arthur M. Mercurio

University of Massachusetts Medical School Faculty Publications

Ferroptosis is an iron-dependent form of programmed cell death characterized by the accumulation of lipid-targeting reactive oxygen species that kill cells by damaging their plasma membrane. The lipid-repair enzyme glutathione peroxidase 4 (GPX4) protects against this oxidative damage and enables cells to resist ferroptosis. Recent work has revealed that matrix-detached carcinoma cells can be susceptible to ferroptosis and that they can evade this fate through the signaling properties of the alpha6beta4 integrin, which sustains GPX4 expression. Although these findings on ferroptosis are provocative, they differ from those in previous studies indicating that matrix-detached cells are prone to apoptosis, via a ...


Imp3 Stabilization Of Wnt5b Mrna Facilitates Taz Activation In Breast Cancer, Sanjoy Samanta, Santosh Guru, Ameer L. Elaimy, John J. Amante, Jianhong Ou, Jun Yu, Lihua Julie Zhu, Arthur M. Mercurio May 2018

Imp3 Stabilization Of Wnt5b Mrna Facilitates Taz Activation In Breast Cancer, Sanjoy Samanta, Santosh Guru, Ameer L. Elaimy, John J. Amante, Jianhong Ou, Jun Yu, Lihua Julie Zhu, Arthur M. Mercurio

University of Massachusetts Medical School Faculty Publications

Insulin-like growth factor-2 mRNA-binding protein 3 (IMP3) is an oncofetal protein associated with many aggressive cancers and implicated in the function of breast cancer stem cells (CSCs). The mechanisms involved, however, are poorly understood. We observed that IMP3 facilitates the activation of TAZ, a transcriptional co-activator of Hippo signaling that is necessary for the function of breast CSCs. The mechanism by which IMP3 activates TAZ involves both mRNA stability and transcriptional regulation. IMP3 stabilizes the mRNA of an alternative WNT ligand (WNT5B) indirectly by repressing miR145-5p, which targets WNT5B, resulting in TAZ activation by alternative WNT signaling. IMP3 also facilitates ...


Jip1-Mediated Jnk Activation Negatively Regulates Synaptic Plasticity And Spatial Memory, Caroline Morel, Tessi Sherrin, Norman J. Kennedy, Kelly H. Forest, Seda Barutcu, Michael Robles, Ezekiel Carpenter-Hyland, Naghum Alfulaij, Claire L. Standen, Robert A. Nichols, Morris Benveniste, Roger J. Davis, Cedomir Todorovic Apr 2018

Jip1-Mediated Jnk Activation Negatively Regulates Synaptic Plasticity And Spatial Memory, Caroline Morel, Tessi Sherrin, Norman J. Kennedy, Kelly H. Forest, Seda Barutcu, Michael Robles, Ezekiel Carpenter-Hyland, Naghum Alfulaij, Claire L. Standen, Robert A. Nichols, Morris Benveniste, Roger J. Davis, Cedomir Todorovic

University of Massachusetts Medical School Faculty Publications

The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JIP1 scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDA receptor currents, increased NMDA receptor-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation. The JIP1 mutant mice also displayed improved hippocampus-dependent spatial memory and enhanced associative fear conditioning. These results were confirmed using a second JIP1 mutant mouse ...


Deconvolution Of Subcellular Protrusion Heterogeneity And The Underlying Actin Regulator Dynamics From Live Cell Imaging, Chuangqi Wang, Hee June Choi, Sung-Jin Kim, Aesha Desai, Namgyu Lee, Dohoon Kim, Yongho Bae, Kwonmoo Lee Jan 2018

Deconvolution Of Subcellular Protrusion Heterogeneity And The Underlying Actin Regulator Dynamics From Live Cell Imaging, Chuangqi Wang, Hee June Choi, Sung-Jin Kim, Aesha Desai, Namgyu Lee, Dohoon Kim, Yongho Bae, Kwonmoo Lee

University of Massachusetts Medical School Faculty Publications

Cell protrusion is morphodynamically heterogeneous at the subcellular level. However, the mechanistic understanding of protrusion activities is usually based on the ensemble average of actin regulator dynamics at the cellular or population levels. Here, we establish a machine learning-based computational framework called HACKS (deconvolution of Heterogeneous Activity Coordination in cytosKeleton at a Subcellular level) to deconvolve the subcellular heterogeneity of lamellipodial protrusion in migrating cells. HACKS quantitatively identifies distinct subcellular protrusion phenotypes from highly heterogeneous protrusion activities and reveals their underlying actin regulator dynamics at the leading edge. Furthermore, it can identify specific subcellular protrusion phenotypes susceptible to pharmacological perturbation ...


The Fission Yeast S-Phase Cyclin Cig2 Can Drive Mitosis, Mira Magner, Daniel L. Keifenheim, Nicholas R. Rhind Nov 2017

The Fission Yeast S-Phase Cyclin Cig2 Can Drive Mitosis, Mira Magner, Daniel L. Keifenheim, Nicholas R. Rhind

University of Massachusetts Medical School Faculty Publications

Commitment to mitosis is regulated by cyclin-dependent kinase (CDK) activity. In the fission yeast Schizosaccharomyces pombe, the major B-type cyclin, Cdc13, is necessary and sufficient to drive mitotic entry. Furthermore, Cdc13 is also sufficient to drive S phase, demonstrating that a single cyclin can regulate alternating rounds of replication and mitosis and providing the foundation of the quantitative model of CDK function. It has been assumed that Cig2, a B-type cyclin expressed only during S-phase and incapable of driving mitosis in wild-type cells, was specialized for S-phase regulation. Here, we show that Cig2 is capable of driving mitosis. Cig2/CDK ...


Ki-67 Contributes To Normal Cell Cycle Progression And Inactive X Heterochromatin In P21 Checkpoint-Proficient Human Cells, Xiaoming Sun, Aizhan Bizhanova, Timothy D. Matheson, Jun Yu, Lihua Julie Zhu, Paul D. Kaufman May 2017

Ki-67 Contributes To Normal Cell Cycle Progression And Inactive X Heterochromatin In P21 Checkpoint-Proficient Human Cells, Xiaoming Sun, Aizhan Bizhanova, Timothy D. Matheson, Jun Yu, Lihua Julie Zhu, Paul D. Kaufman

University of Massachusetts Medical School Faculty Publications

Ki-67 protein is widely used as a tumor proliferation marker. However, whether Ki-67 affects cell cycle progression has been controversial. Here, we demonstrate that depletion of Ki-67 in human hTERT-RPE1, WI-38, IMR90, hTERT-BJ cell lines and primary fibroblast cells slowed entry into S phase and coordinately downregulated genes related to DNA replication. Some gene expression changes were partially relieved in Ki-67-depleted hTERT-RPE1 cells by co-depletion of the Rb checkpoint protein, but more thorough suppression of the transcriptional and cell cycle defects was observed upon depletion of cell cycle inhibitor p21. Notably, induction of p21 upon depletion of Ki-67 was a ...