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Full-Text Articles in Biology
Micron-Scale Plasma Membrane Curvature Is Recognized By The Septin Cytoskeleton, Andrew A. Bridges, Maximilian S. Jentzsch, Patrick W. Oakes, Patricia Occhipinti, Amy S. Gladfelter
Micron-Scale Plasma Membrane Curvature Is Recognized By The Septin Cytoskeleton, Andrew A. Bridges, Maximilian S. Jentzsch, Patrick W. Oakes, Patricia Occhipinti, Amy S. Gladfelter
Dartmouth Scholarship
Cells change shape in response to diverse environmental and developmental conditions, creating topologies with micron-scale features. Although individual proteins can sense nanometer-scale membrane curvature, it is unclear if a cell could also use nanometer-scale components to sense micron-scale contours, such as the cytokinetic furrow and base of neuronal branches. Septins are filament-forming proteins that serve as signaling platforms and are frequently associated with areas of the plasma membrane where there is micron-scale curvature, including the cytokinetic furrow and the base of cell protrusions. We report here that fungal and human septins are able to distinguish between different degrees of micron-scale …
Mechanisms Of Signal Transduction By Ethylene: Overlapping And Non-Overlapping Signalling Roles In A Receptor Family, Samina N. Shakeel, Xiaomin Wang, Brad M. Binder, G. Eric Schaller
Mechanisms Of Signal Transduction By Ethylene: Overlapping And Non-Overlapping Signalling Roles In A Receptor Family, Samina N. Shakeel, Xiaomin Wang, Brad M. Binder, G. Eric Schaller
Dartmouth Scholarship
The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional regulation within the nucleus. Here, we present our current understanding of ethylene signal transduction, focusing on recent developments that support a model with overlapping and non-overlapping roles for members of the ethylene receptor family. We consider the evidence supporting this model for sub-functionalization within the receptor …
Vegf And Angiopoietin-1 Exert Opposing Effects On Cell Junctions By Regulating The Rho Gef Syx, Siu P. Ngok, Rory Geyer, Miaoliang Liu, Antonis Kourtidis, Sudesh Agrawal, Chuanshen Wu, Himabindu Reddy Seerapu, Laura J. Lewis-Tuffin, Karen L. Moodie, Deborah Huveldt, Ruth Marx, Jay M. Baraban, Peter Storz, Arie Horowitz, Panos Z. Anastasiadis
Vegf And Angiopoietin-1 Exert Opposing Effects On Cell Junctions By Regulating The Rho Gef Syx, Siu P. Ngok, Rory Geyer, Miaoliang Liu, Antonis Kourtidis, Sudesh Agrawal, Chuanshen Wu, Himabindu Reddy Seerapu, Laura J. Lewis-Tuffin, Karen L. Moodie, Deborah Huveldt, Ruth Marx, Jay M. Baraban, Peter Storz, Arie Horowitz, Panos Z. Anastasiadis
Dartmouth Scholarship
Vascular endothelial growth factor (VEGF) and Ang1 (Angiopoietin-1) have opposing effects on vascular permeability, but the molecular basis of these effects is not fully known. We report in this paper that VEGF and Ang1 regulate endothelial cell (EC) junctions by determining the localization of the RhoA-specific guanine nucleotide exchange factor Syx. Syx was recruited to junctions by members of the Crumbs polarity complex and promoted junction integrity by activating Diaphanous. VEGF caused translocation of Syx from cell junctions, promoting junction disassembly, whereas Ang1 maintained Syx at the junctions, inducing junction stabilization. The VEGF-induced translocation of Syx from EC junctions was …
Arabidopsis Bhlh100 And Bhlh101 Control Iron Homeostasis Via A Fit-Independent Pathway, Alicia B. Sivitz, Victor Hermand, Catherine Curie, Grégory Vert
Arabidopsis Bhlh100 And Bhlh101 Control Iron Homeostasis Via A Fit-Independent Pathway, Alicia B. Sivitz, Victor Hermand, Catherine Curie, Grégory Vert
Dartmouth Scholarship
Iron deficiency induces a complex set of responses in plants, including developmental and physiological changes, to increase iron uptake from soil. In Arabidopsis, many transporters involved in the absorption and distribution of iron have been identified over the past decade. However, little is known about the signaling pathways and networks driving the various responses to low iron. Only the basic helix–loop–helix (bHLH) transcription factor FIT has been shown to control the expression of the root iron uptake machinery genes FRO2 and IRT1. Here, we characterize the biological role of two other iron-regulated transcription factors, bHLH100 and bHLH101, in iron homeostasis. …
Two-Component Elements Mediate Interactions Between Cytokinin And Salicylic Acid In Plant Immunity, Cristiana T. Argueso, Fernando J. Ferreira, Petra Epple, Jennifer P.C To, Claire E. Hutchison, G. Eric Schaller, Jeffrey L. Dangl, Joseph J. Kieber
Two-Component Elements Mediate Interactions Between Cytokinin And Salicylic Acid In Plant Immunity, Cristiana T. Argueso, Fernando J. Ferreira, Petra Epple, Jennifer P.C To, Claire E. Hutchison, G. Eric Schaller, Jeffrey L. Dangl, Joseph J. Kieber
Dartmouth Scholarship
Recent studies have revealed an important role for hormones in plant immunity. We are now beginning to understand the contribution of crosstalk among different hormone signaling networks to the outcome of plant–pathogen interactions. Cytokinins are plant hormones that regulate development and responses to the environment. Cytokinin signaling involves a phosphorelay circuitry similar to two-component systems used by bacteria and fungi to perceive and react to various environmental stimuli. In this study, we asked whether cytokinin and components of cytokinin signaling contribute to plant immunity. We demonstrate that cytokinin levels in Arabidopsis are important in determining the amplitude of immune responses, …
Global Analysis Of Serine-Threonine Protein Kinase Genes In Neurospora Crassa, Gyungsoon Park, Jacqueline A. Servin, Gloria E. Turner, Lorena Altamirano
Global Analysis Of Serine-Threonine Protein Kinase Genes In Neurospora Crassa, Gyungsoon Park, Jacqueline A. Servin, Gloria E. Turner, Lorena Altamirano
Dartmouth Scholarship
Serine/threonine (S/T) protein kinases are crucial components of diverse signaling pathways in eukaryotes, including the model filamentous fungus Neurospora crassa. In order to assess the importance of S/T kinases to Neurospora biology, we embarked on a global analysis of 86 S/T kinase genes in Neurospora. We were able to isolate viable mutants for 77 of the 86 kinase genes. Of these, 57% exhibited at least one growth or developmental phenotype, with a relatively large fraction (40%) possessing a defect in more than one trait. S/T kinase knockouts were subjected to chemical screening using a panel of eight chemical treatments, with …
Ceramide Kinase Regulates Phospholipase C And Phosphatidylinositol 4, 5, Bisphosphate In Phototransduction, Ujjaini Dasgupta, Takeshi Bamba, Salvatore Chiantia, Pusha Karim, Ahmad N. Abou Tayoun
Ceramide Kinase Regulates Phospholipase C And Phosphatidylinositol 4, 5, Bisphosphate In Phototransduction, Ujjaini Dasgupta, Takeshi Bamba, Salvatore Chiantia, Pusha Karim, Ahmad N. Abou Tayoun
Dartmouth Scholarship
Phosphoinositide-specific phospholipase C (PLC) is a central effector for many biological responses regulated by G-protein-coupled receptors including Drosophila phototransduction where light sensitive channels are activated downstream of NORPA, a PLCbeta homolog. Here we show that the sphingolipid biosynthetic enzyme, ceramide kinase, is a novel regulator of PLC signaling and photoreceptor homeostasis. A mutation in ceramide kinase specifically leads to proteolysis of NORPA, consequent loss of PLC activity, and failure in light signal transduction. The mutant photoreceptors also undergo activity-dependent degeneration. Furthermore, we show that a significant increase in ceramide, resulting from lack of ceramide kinase, perturbs the membrane microenvironment of …
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Dartmouth Scholarship
Understanding how nutrients affect gene expression will help us to understand the mechanisms controlling plant growth and development as a function of nutrient availability. Nitrate has been shown to serve as a signal for the control of gene expression in Arabidopsis. There is also evidence, on a gene-by-gene basis, that downstream products of nitrogen (N) assimilation such as glutamate (Glu) or glutamine (Gln) might serve as signals of organic N status that in turn regulate gene expression. To identify genome-wide responses to such organic N signals, Arabidopsis seedlings were transiently treated with ammonium nitrate in the presence or absence of …
The Role Of Carcinine In Signaling At The Drosophila Photoreceptor Synapse, Brendan A. Gavin, Susan E. Arruda, Patrick J. Dolph
The Role Of Carcinine In Signaling At The Drosophila Photoreceptor Synapse, Brendan A. Gavin, Susan E. Arruda, Patrick J. Dolph
Dartmouth Scholarship
The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG) analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a …
A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber
A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber
Dartmouth Scholarship
The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of …