scholarly journals GIV/Girdin and Exo70 Constitute the Core of the Mammalian Polarized Exocytic Machinery

2019 ◽  
Author(s):  
Cristina Rohena ◽  
Navin Rajapakse ◽  
I-Chung Lo ◽  
Peter Novick ◽  
Debashis Sahoo ◽  
...  
Keyword(s):  
Matrix Metalloproteases ◽  
Regulatory Control ◽  
List Type ◽  
Linear Motif ◽  
Linear Interaction ◽  
Spatial Control ◽  
Disease States ◽  
Cargo Proteins ◽  
And Migration ◽  
Polarized Exocytosis

SUMMARYPolarized exocytosis is a fundamental process by which membrane and cargo proteins are delivered to the plasma membrane with precise spatial control; it is essential for cell growth, morphogenesis, and migration. Although the need for the octameric exocyst complex is conserved from yeast to humans, what imparts spatial control is known only in yeast, i.e., a polarity scaffold without mammalian homolog, called Bem1p. We demonstrate that polarity scaffold GIV/Girdin fulfills the key criteria and functions of its yeast counterpart Bem1p. Both Bem1p and GIV bind yeast and mammalian Exo70 proteins via similar short-linear interaction motifs, but each preferentially binds its evolutionary counterpart. In cells where this GIV•Exo-70 interaction is selectively disrupted, delivery of the metalloprotease MT1-MMP to podosomes, collagen degradation and haptotaxis through basement membrane matrix were impaired. GIV’s interacting partners reveal other components of polarized exocytosis in mammals. Findings not only expose how GIV “upgrades” the exocytic process in mammals, but also how the ability to regulate exocytosis shapes GIV’s ability to fuel metastasis.GRAPHIC ABSTRACTGraphic Abstract: Schematic comparing the components of polarized exocytosis, i.e., the major polarity scaffold in yeast (Bem1p; left) and humans (Girdin; right) and the various cellular components and signaling mechanisms that are known to converge on them.The eTOC blurbPolarized exocytosis is a precision-controlled process that is enhanced in disease states, e.g., cancer invasion; what imparts polarity was unknown. Authors reveal how the process underwent an evolutionary upgrade from yeast to humans by pinpointing GIV/Girdin as the polarity scaffold which orchestrates the exocytosis of matrix metalloproteases during cell invasion.HIGHLIGHTSGIV (human) and Bem1p (yeast) bind Exo70; are required for exocytosisGIV binds and aids PM localization Exo70 via a conserved short linear motifBinding facilitates MT1-MMP delivery to podosomes, ECM degradation, invasionRegulatory control over polarized exocytosis is upgraded during evolution

scholarly journals AP-4 vesicles contribute to spatial control of autophagy via RUSC-dependent peripheral delivery of ATG9A

2017 ◽  
Author(s):  
Alexandra K. Davies ◽  
Daniel N. Itzhak ◽  
James R. Edgar ◽  
Tara L. Archuleta ◽  
Jennifer Hirst ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Close Association ◽  
Adaptor Protein ◽  
Cell Types ◽  
Subcellular Localisation ◽  
Cell Periphery ◽  
Accessory Proteins ◽  
Unknown Aetiology ◽  
Spatial Control ◽  
Cargo Proteins

AbstractAdaptor protein 4 (AP-4) is an ancient membrane trafficking complex, whose function has largely remained elusive. In humans, AP-4 deficiency causes a severe neurological disorder of unknown aetiology. We apply unbiased proteomic methods, including ‘Dynamic Organellar Maps’, to find proteins whose subcellular localisation depends on AP-4. We identify three transmembrane cargo proteins, ATG9A, SERINC1 and SERINC3, and two AP-4 accessory proteins, RUSC1 and RUSC2. We demonstrate that AP-4 deficiency causes missorting of ATG9A in diverse cell types, including patient-derived cells, as well as dysregulation of autophagy. RUSC2 facilitates the transport of AP-4-derived, ATG9A-positive vesicles from the TGN to the cell periphery. These vesicles cluster in close association with autophagosomes, suggesting they are the “ATG9A reservoir” required for autophagosome biogenesis. Our study uncovers ATG9A trafficking as a ubiquitous function of the AP-4 pathway. Furthermore, it provides a potential molecular pathomechanism of AP-4 deficiency, through dysregulated spatial control of autophagy.

scholarly journals Cis-regulatory control of the SM50 gene, an early marker of skeletogenic lineage specification in the sea urchin embryo

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 1957-1970 ◽  
Author(s):  
K.W. Makabe ◽  
C.V. Kirchhamer ◽  
R.J. Britten ◽  
E.H. Davidson
Keyword(s):  
Transcription Start Site ◽  
Sea Urchin ◽  
Regulatory Elements ◽  
Regulatory Control ◽  
Control Element ◽  
Start Site ◽  
Transcription Start ◽  
Sequence Element ◽  
Spatial Control ◽  
Sea Urchin Embryo

The SM50 gene encodes a minor matrix protein of the sea urchin embryo spicule. We carried out a detailed functional analysis of a cis-regulatory region of this gene, extending 440 bp upstream and 120 bp downstream of the transcription start site, that had been shown earlier to confer accurate skeletogenic expression of an injected expression vector. The distal portion of this fragment contains elements controlling amplitude of expression, while the region from −200 to +105 contains spatial control elements that position expression accurately in the skeletogenic lineages of the embryo. A systematic mutagenesis analysis of this region revealed four adjacent regulatory elements, viz two copies of a positively acting sequence (element D) that are positioned just upstream of the transcription start site; an indispensable spatial control element (element C) that is positioned downstream of the start site; and further downstream, a second positively acting sequence (element A). We then constructed a series of synthetic expression constructs. These contained oligonucleotides representing normal and mutated versions of elements D, C, and A, in various combinations. We also changed the promoter of the SM50 gene from a TATA-less to a canonical TATA box form, without any effect on function. Perfect spatial regulation was also produced by a final series of constructs that consisted entirely of heterologous enhancers from the CyIIIa gene, the SV40 early promoter, and synthetic D, C, and A elements. We demonstrate that element C exercises the primary spatial control function of the region we analyzed. We term this a ‘locator’ element. This differs from conventional ‘tissue-specific enhancers’ in that while it is essential for expression, it has no transcriptional activity on its own, and it requires other, separable, positive regulatory elements for activity. In the normal configuration these ancillary positive functions are mediated by elements A and D. Only positively acting control elements were observed in the SM50 regulatory domain throughout this analysis.

scholarly journals Resolving the transcriptional transitions associated with oligodendrocyte generation from adult neural stem cells by single cell sequencing

2020 ◽  
Author(s):  
Kasum Azim ◽  
Filippo Calzolari ◽  
Martina Cantone ◽  
Rainer Akkermann ◽  
Julio Vera ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Single Cell ◽  
Signaling Pathways ◽  
Regulatory Control ◽  
Transcriptional Networks ◽  
Detailed Knowledge ◽  
List Type ◽  
Specific Expression ◽  
Gene Regulatory

AbstractThe subventricular zone (SVZ) is the largest neurogenic niche in the adult forebrain. Notably, neural stem cells (NSCs) of the SVZ generate not only neurons, but also oligodendrocytes, the myelin-forming cells of the central nervous system. Transcriptomic studies have provided detailed knowledge of the molecular events that regulate neurogenesis, but little is understood about adult oligodendrogenesis from SVZ-NSCs. To address this, we performed in-depth single-cell transcriptomic analyses to resolve the major differences in neuronal and oligodendroglial lineages derived from the adult SVZ. A hallmark of adult oligodendrogenesis was the stage-specific expression of transcriptional modulators that regulate developmental oligodendrogenesis. Notably, divergence of the oligodendroglial lineage was distinguished by Wnt-Notch and angiogenesis-related signaling, whereas G-protein-coupled receptor signaling pathways were the major signature observed in the neurogenic lineage. Moreover, in-depth gene regulatory network analysis identified key stage-specific master regulators of the oligodendrocyte lineage and revealed new mechanisms by which signaling pathways interact with transcriptional networks to control lineage progression. Our work provides an integrated view of the multi-step differentiation process leading from NSCs to mature oligodendrocytes, by linking environmental signals to known and novel transcriptional mechanisms orchestrating oligodendrogenesis.Main pointsDistinct adult NSC populations giving rise to either oligodendrocytes or neurons can be identified by the expression of transcription factors.Gene regulatory control of oligodendrogenesis is a major fate-determinant for their generation.

scholarly journals Inhibition of ITK differentiates GVT and GVHD in allo-HSCT

2020 ◽  
Author(s):  
Mahinbanu Mammadli ◽  
Weishan Huang ◽  
Rebecca Harris ◽  
Aisha Sultana ◽  
Ying Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
Inflammatory Cytokines ◽  
Treatment Strategies ◽  
Peptide Inhibitor ◽  
List Type ◽  
Hematopoietic Stem ◽  
Target Organs ◽  
Donor T Cells ◽  
Novel Treatment Strategies ◽  
And Migration

AbstractAllogeneic hematopoietic stem cell transplantation is a life-saving treatment for many malignant and nonmalignant diseases. Donor T cells contained within the graft prevent tumor recurrence via graft-versus-tumor (GVT) effects, however, also cause graft-versus-host disease (GVHD). Novel treatment strategies are therefore needed to allow maintenance of GVT while suppressing GVHD. Here we show using murine models, that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving the beneficial GVT effects. Donor T cells from Itk-/- mice exhibit significantly reduced production of inflammatory cytokines and migration to GVHD target organs such as liver and small intestine, while maintaining GVT efficacy against primary B-ALL tumors. Itk-/- T cells exhibited reduced expression of IRF4 and decreased JAK/STAT signaling activity, but preserved cytotoxicity, which was accompanied by upregulation of Eomesodermin (Eomes), which was necessary for GVT function. A novel peptide inhibitor ITK signaling is also able to prevent GVHD. This novel peptide inhibitor also reduced cytokine production in mice and human T cells. Altogether, our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVT effects following allo-HSCT treatment.Key PointsInhibiting ITK by a novel peptide significantly reduces GVHD but retains GVT.ITK deficient donor T cells exhibit minimal GVHD, but maintain GVT activity.ITK deficient donor T cells exhibit significantly reduced production of inflammatory cytokines and migration to GVHD target organs.Eomes is required for GVT effect.

scholarly journals Congenital CMV Infection Presenting with Massive Intracerebral Hemorrhage

2021 ◽  
Vol 48 (s2) ◽  
pp. S8-S8
Author(s):  
Barbra deVrijer ◽  
Diana Crowley ◽  
Delaney Cosma ◽  
Giulio Muscedere ◽  
Robert Hammond
Keyword(s):  
Intracerebral Hemorrhage ◽  
Developing Brain ◽  
List Type ◽  
Cmv Infection ◽  
Congenital Cmv Infection ◽  
And Migration ◽  
Stillborn Infant ◽  
Intrauterine Infections ◽  
Developing Nervous System ◽  
Congenital Cmv

Cytomegalovirus (CMV) is among the most common of intrauterine infections against which we have no effective preventative or therapeutic options. The developing nervous system is a frequent target of CMV and while most injuries are subclinical, severe insults leading to microcephaly and migration defects are well known. A 20-week gestational age fetus was found to have several abnormalities on prenatal ultrasound, the most prominent of which was a large echogenic focus in one cerebral hemisphere. Congenital CMV infection was identified by amniocentesis and maternal serology. The pregnancy was ended by early induction of labour for a 368g stillborn infant. Postmortem examination revealed massive intracerebral hemorrhage as the correlate for the sonographic finding. The microscopic examination of the brain was also striking for extensive polymicrogyria, a high burden of CMV and abundant angiocentric CMV pathology. Catastrophic intracerebral hemorrhage has not been previously reported in association with congenital CMV infection. The present case expands the range of potential injuries the developing brain is subject to in the setting of CMV infection and raises the possibility of a direct vascular injury.Learning ObjectivesConsider intracerebral hemorrhage in the range of potential outcomes in congenital CMV infectionDescribe how polymicrogyria may result from an insult during proliferation and migrationDiscuss possible mechanisms of injury to the developing brain by CMV

scholarly journals GIV•Kindlin interaction is required for Kindlin-Mediated Integrin Recognition and Activation

2019 ◽  
Author(s):  
Cristina Rohena ◽  
Nicholas Kalogriopoulos ◽  
Navin Rajapakse ◽  
Suchismita Roy ◽  
Inmaculada Lopez-Sanchez ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cancer Metastasis ◽  
List Type ◽  
Β1 Integrin ◽  
Nucleotide Exchange ◽  
Integrin Activation ◽  
Tumor Cell Adhesion ◽  
Linear Motif ◽  
C Terminus

ABSTRACTCells perceive and respond to the extracellular matrix (ECM) via integrin receptors; their dysregulation has been implicated in inflammation and cancer metastasis. Here we show that a guanine nucleotide exchange modulator of trimeric-GTPase Gαi, GIV (a.k.a Girdin), directly binds the integrin adaptor Kindlin-2. A non-canonical short linear motif within GIV’s C-terminus binds Kindlin-2-FERM3 domain at a site that is distinct from the binding site for the canonical NPxY motif on the -integrin tail. Binding of GIV to Kindlin-2 allosterically enhances Kindlin-2’s affinity for β1-integrin. Consequently, integrin activation and clustering are maximized, which augments cell adhesion, spreading and invasion. Findings elucidate how the GIV•Kindlin-2 complex has a two-fold impact: it allosterically synergizes integrin activation and enables β1-integrins to indirectly access and modulate trimeric GTPases via the complex. Furthermore, Cox proportional-hazard models on tumor transcriptomics provide trans-scale evidence of synergistic interactions between GIV•Kindlin-2•β1-integrin on time to progression to metastasis.The eTOC blurbIntegrins mediate cell adhesion to the extracellular matrix; their dysregulation fuels inflammation, cancer cell invasion and metastasis. Authors show how two pro-metastatic scaffold proteins, Kindlin and GIV/Girdin bind and cooperatively enhance their allosteric coupling to integrins, and their subsequent activation. Findings reveal novel interfaces in integrin signaling for pharmacologic manipulation.HIGHLIGHTSGIV and Kindlin(K2), two integrin adaptors that promote metastasis, bind each otherBinding of GIV or integrin to K2 allosterically enhances GIV•K2•integrin complexesBinding is required for the maximal recruitment of GIV and K2 to active integrinsBinding facilitates integrin clustering, activation, tumor cell adhesion, invasion.

scholarly journals State Dependent Beta Oscillations in the Cortico-Basal Ganglia Circuit and their Neuromodulation under Phase-Locked Inputs

2020 ◽  
Author(s):  
Timothy O. West ◽  
Simon F. Farmer ◽  
Peter J. Magill ◽  
Andrew Sharott ◽  
Vladimir Litvak ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Brain Stimulation ◽  
Open Loop ◽  
List Type ◽  
Beta Band ◽  
Beta Oscillations ◽  
Disease States ◽  
State Dependent ◽  
Brain Rhythm ◽  
Brain States

AbstractState-of-the-art therapeutic brain stimulation strategies are delivered open loop, using fixed parameters. However, brain states exhibit spontaneous fluctuations dependent upon different behavioural or disease states. Here, we use a model of the cortico-basal ganglia-thalamic circuit to demonstrate how connectivity underpins changes in subcortical beta oscillations – a commonly used control parameter for deep brain stimulation in Parkinson’s disease. We show that recurrent cortical-subcortical loops involving either the cortico-subthalamic or pallido-subthalamic pathways can act in antagonism to modulate the expression of beta band activity (14-30 Hz). These pathways alter the relative timing of intermittent activity across the network, with increased pallido-subthalamic connectivity increasing the propensity of the circuit to enter a state of autonomous oscillation. We demonstrate that phase-locked stimulation can modulate these oscillations, with an efficacy that ultimately depends upon the connectivity across the circuit. This work outlines critical factors required to implement state-adaptive closed-loop brain stimulation.HighlightsConverging inputs to the subthalamic nucleus arriving via the external segment of globus pallidus and cortex act in antagonism and promote different beta rhythms.Phase locked stimulation has the capacity to selectively enhance or suppress a brain rhythm depending on the stimulation timing.The efficacy of stimulation and the parameters required to deliver it, e.g. stimulation timing, effective sensing and stimulation locations, are functions of network state.

scholarly journals Individual-based simulations of genome evolution with ancestry: the GenomeAdmixR R package

2020 ◽  
Author(s):  
Thijs Janzen ◽  
Fernando Diaz
Keyword(s):  
Genome Evolution ◽  
R Package ◽  
List Type ◽  
Analytical Treatment ◽  
Local Ancestry ◽  
Mechanistic Approach ◽  
And Migration ◽  
Set Up ◽  
User Friendly ◽  
Genomic Patterns

ABSTRACTHybridization between populations or species results in a mosaic of the two parental genomes. Genome admixture has received increasing attention for its implications in speciation, human evolution, Evolve and Resequencing (E&R) and genetic mapping. However, a thorough understanding of how local ancestry changes after admixture, and how selection affects patterns of local ancestry remains elusive. The complexity of these questions limits analytical treatment, but these scenarios are specifically suitable for simulation. Currently, there is no simulation framework that models whole-genome evolution of local ancestry following admixture.Here, we present the R package GenomeAdmixR, which uses an individual-based model to simulate genomic patterns of local ancestry following admixture forward in time. GenomeAdmixR provides user-friendly functions to set up and analyze simulations under evolutionary scenarios with selection, linkage and migration.We show the flexible functionality of the GenomeAdmixR workflow by demonstrating 1) how to design an E&R simulation using GenomeAdmixR and 2) how to use GenomeAdmixR to verify analytical expectations following from the theory of junctions.GenomeAdmixR provides a mechanistic approach to explore expected genome responses to realistic admixture scenarios. With this package, we aim to aid researchers in testing specific hypotheses based on empirical findings involving admixing populations.

scholarly journals Co-regulatory networks of human serum proteins link genetics to disease

Science ◽  
2018 ◽  
Vol 361 (6404) ◽  
pp. 769-773 ◽  
Author(s):  
Valur Emilsson ◽  
Marjan Ilkov ◽  
John R. Lamb ◽  
Nancy Finkel ◽  
Elias F. Gudmundsson ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Complex Disease ◽  
Serum Proteins ◽  
Extracellular Proteins ◽  
Regulatory Control ◽  
Pairwise Correlation ◽  
Disease States ◽  
Age Related ◽  
Network Modules ◽  
Cis And Trans

Proteins circulating in the blood are critical for age-related disease processes; however, the serum proteome has remained largely unexplored. To this end, 4137 proteins covering most predicted extracellular proteins were measured in the serum of 5457 Icelanders over 65 years of age. Pairwise correlation between proteins as they varied across individuals revealed 27 different network modules of serum proteins, many of which were associated with cardiovascular and metabolic disease states, as well as overall survival. The protein modules were controlled by cis- and trans-acting genetic variants, which in many cases were also associated with complex disease. This revealed co-regulated groups of circulating proteins that incorporated regulatory control between tissues and demonstrated close relationships to past, current, and future disease states.

Sign in / Sign up

Export Citation Format

Share Document