scholarly journals Heterodimer-heterotetramer formation mediates enhanced sensor activity in a biophysical model for BMP signaling

2021 ◽  
Vol 17 (9) ◽  
pp. e1009422
Author(s):  
M. Shahriar Karim ◽  
Aasakiran Madamanchi ◽  
James A. Dutko ◽  
Mary C. Mullins ◽  
David M. Umulis
Keyword(s):  
Distinct Type ◽  
Cell Types ◽  
Bmp Signaling ◽  
Biophysical Model ◽  
Transmembrane Receptors ◽  
Bmp Receptors ◽  
Morphogenetic Protein ◽  
Wide Range ◽  
Multiple Cell ◽  
Organismal Development

Numerous stages of organismal development rely on the cellular interpretation of gradients of secreted morphogens including members of the Bone Morphogenetic Protein (BMP) family through transmembrane receptors. Early gradients of BMPs drive dorsal/ventral patterning throughout the animal kingdom in both vertebrates and invertebrates. Growing evidence in Drosophila, zebrafish, murine and other systems suggests that BMP ligand heterodimers are the primary BMP signaling ligand, even in systems in which mixtures of BMP homodimers and heterodimers are present. Signaling by heterodimers occurs through a hetero-tetrameric receptor complex comprising of two distinct type one BMP receptors and two type II receptors. To understand the system dynamics and determine whether kinetic assembly of heterodimer-heterotetramer BMP complexes is favored, as compared to other plausible BMP ligand-receptor configurations, we developed a kinetic model for BMP tetramer formation based on current measurements for binding rates and affinities. We find that contrary to a common hypothesis, heterodimer-heterotetramer formation is not kinetically favored over the formation of homodimer-tetramer complexes under physiological conditions of receptor and ligand concentrations and therefore other mechanisms, potentially including differential kinase activities of the formed heterotetramer complexes, must be the cause of heterodimer-heterotetramer signaling primacy. Further, although BMP complex assembly favors homodimer and homomeric complex formation over a wide range of parameters, ignoring these signals and instead relying on the heterodimer improves the range of morphogen interpretation in a broad set of conditions, suggesting a performance advantage for heterodimer signaling in patterning multiple cell types in a gradient.

scholarly journals Different Routes of Bone Morphogenic Protein (BMP) Receptor Endocytosis Influence BMP Signaling

2006 ◽  
Vol 26 (20) ◽  
pp. 7791-7805 ◽  
Author(s):  
Anke Hartung ◽  
Keren Bitton-Worms ◽  
Maya Mouler Rechtman ◽  
Valeska Wenzel ◽  
Jan H. Boergermann ◽  
...  
Keyword(s):  
Transcriptional Response ◽  
Bmp Signaling ◽  
Signaling Cascades ◽  
Type I ◽  
Coated Pits ◽  
Transmembrane Receptors ◽  
Caveolin 1 ◽  
Bmp Receptor ◽  
Bmp Receptors ◽  
Morphogenetic Protein

ABSTRACT Endocytosis is important for a variety of functions in eukaryotic cells, including the regulation of signaling cascades via transmembrane receptors. The internalization of bone morphogenetic protein (BMP) receptor type I (BRI) and type II (BRII) and its relation to signaling were largely unexplored. Here, we demonstrate that both receptor types undergo constitutive endocytosis via clathrin-coated pits (CCPs) but that only BRII undergoes also caveola-like internalization. Using several complementary approaches, we could show that (i) BMP-2-mediated Smad1/5 phosphorylation occurs at the plasma membrane in nonraft regions, (ii) continuation of Smad signaling resulting in a transcriptional response requires endocytosis via the clathrin-mediated route, and (iii) BMP signaling leading to alkaline phosphatase induction initiates from receptors that fractionate into cholesterol-enriched, detergent-resistant membranes. Furthermore, we show that BRII interacts with Eps15R, a constitutive component of CCPs, and with caveolin-1, the marker protein of caveolae. Taken together, the localization of BMP receptors in distinct membrane domains is prerequisite to their taking different endocytosis routes with specific impacts on Smad-dependent and Smad-independent signaling cascades.

scholarly journals A versatile automated high-throughput drug screening platform for zebrafish embryos

2020 ◽  
Author(s):  
Alexandra Lubin ◽  
Jason Otterstrom ◽  
Yvette Hoade ◽  
Ivana Bjedov ◽  
Eleanor Stead ◽  
...  
Keyword(s):  
High Throughput ◽  
Drug Screening ◽  
Imaging System ◽  
Cell Types ◽  
Wide Range ◽  
Stem And Progenitor Cells ◽  
Multiple Cell ◽  
Flexible Imaging ◽  
Automated Screening ◽  
Screening Platform

AbstractZebrafish provide a unique opportunity for drug screening in living animals, with the fast developing, transparent embryos allowing for relatively high throughput, microscopy-based screens. However, the limited availability of rapid, flexible imaging and analysis platforms has limited the use of zebrafish in drug screens. We have developed a easy-to-use, customisable automated screening procedure suitable for high-throughput phenotype-based screens of live zebrafish. We utilised the WiScan®Hermes High Content Imaging System to rapidly acquire brightfield and fluorescent images of embryos, and the WiSoft®Athena Zebrafish Application for analysis, which harnesses an Artificial Intelligence-driven algorithm to automatically detect fish in brightfield images, identify anatomical structures, partition the animal into regions, and exclusively select the desired side-oriented fish. Our initial validation combined structural analysis with fluorescence images to enumerate GFP-tagged haematopoietic stem and progenitor cells in the tails of embryos, which correlated with manual counts. We further validated this system to assess the effects of genetic mutations and x-ray irradiation in high content using a wide range of assays. Further, we performed simultaneous analysis of multiple cell types using dual fluorophores in high throughput. In summary, we demonstrate a broadly applicable and rapidly customisable platform for high content screening in zebrafish.

Bmp signaling regulates proximal-distal differentiation of endoderm in mouse lung development

Development ◽  
1999 ◽  
Vol 126 (18) ◽  
pp. 4005-4015 ◽  
Author(s):  
M. Weaver ◽  
J.M. Yingling ◽  
N.R. Dunn ◽  
S. Bellusci ◽  
B.L. Hogan
Keyword(s):  
Cell Types ◽  
Surfactant Protein ◽  
Bmp Signaling ◽  
Dominant Negative ◽  
Clara Cell ◽  
Mouse Lung ◽  
Marker Genes ◽  
Distal Marker ◽  
Morphogenetic Protein

In the mature mouse lung, the proximal-distal (P-D) axis is delineated by two distinct epithelial subpopulations: the proximal bronchiolar epithelium and the distal respiratory epithelium. Little is known about the signaling molecules that pattern the lung along the P-D axis. One candidate is Bone Morphogenetic Protein 4 (Bmp4), which is expressed in a dynamic pattern in the epithelial cells in the tips of growing lung buds. Previous studies in which Bmp4 was overexpressed in the lung endoderm (Bellusci, S., Henderson, R., Winnier, G., Oikawa, T. and Hogan, B. L. M. (1996) Development 122, 1693–1702) suggested that this factor plays an important role in lung morphogenesis. To further investigate this question, two complementary approaches were utilized to inhibit Bmp signaling in vivo. The Bmp antagonist Xnoggin and, independently, a dominant negative Bmp receptor (dnAlk6), were overexpressed using the surfactant protein C (Sp-C) promoter/enhancer. Inhibiting Bmp signaling results in a severe reduction in distal epithelial cell types and a concurrent increase in proximal cell types, as indicated by morphology and expression of marker genes, including the proximally expressed hepatocyte nuclear factor/forkhead homologue 4 (Hfh4) and Clara cell marker CC10, and the distal marker Sp-C. In addition, electron microscopy demonstrates the presence of ciliated cells, a proximal cell type, in the most peripheral regions of the transgenic lungs. We propose a model in which Bmp4 is a component of an apical signaling center controlling P-D patterning. Endodermal cells at the periphery of the lung, which are exposed to high levels of Bmp4, maintain or adopt a distal character, while cells receiving little or no Bmp4 signal initiate a proximal differentiation program.

scholarly journals The bone morphogenetic protein axis is a positive regulator of skeletal muscle mass

2013 ◽  
Vol 203 (2) ◽  
pp. 345-357 ◽  
Author(s):  
Catherine E. Winbanks ◽  
Justin L. Chen ◽  
Hongwei Qian ◽  
Yingying Liu ◽  
Bianca C. Bernardo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Bone Morphogenetic Protein ◽  
Signaling Pathway ◽  
Muscle Mass ◽  
Muscle Wasting ◽  
Muscle Growth ◽  
Bmp Signaling ◽  
Positive Regulator ◽  
Bmp Receptors ◽  
Morphogenetic Protein

Although the canonical transforming growth factor β signaling pathway represses skeletal muscle growth and promotes muscle wasting, a role in muscle for the parallel bone morphogenetic protein (BMP) signaling pathway has not been defined. We report, for the first time, that the BMP pathway is a positive regulator of muscle mass. Increasing the expression of BMP7 or the activity of BMP receptors in muscles induced hypertrophy that was dependent on Smad1/5-mediated activation of mTOR signaling. In agreement, we observed that BMP signaling is augmented in models of muscle growth. Importantly, stimulation of BMP signaling is essential for conservation of muscle mass after disruption of the neuromuscular junction. Inhibiting the phosphorylation of Smad1/5 exacerbated denervation-induced muscle atrophy via an HDAC4-myogenin–dependent process, whereas increased BMP–Smad1/5 activity protected muscles from denervation-induced wasting. Our studies highlight a novel role for the BMP signaling pathway in promoting muscle growth and inhibiting muscle wasting, which may have significant implications for the development of therapeutics for neuromuscular disorders.

scholarly journals Antitumoral Activities of Curcumin and Recent Advances to ImProve Its Oral Bioavailability

Biomedicines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1476
Author(s):  
Marta Claudia Nocito ◽  
Arianna De Luca ◽  
Francesca Prestia ◽  
Paola Avena ◽  
Davide La Padula ◽  
...  
Keyword(s):  
Curcuma Longa ◽  
Cell Types ◽  
In Vivo Studies ◽  
Beneficial Effects ◽  
Bioactive Component ◽  
Wide Range ◽  
Multiple Cell ◽  
Cycle Regulation ◽  
Cell Signaling Pathways

Curcumin, a main bioactive component of the Curcuma longa L. rhizome, is a phenolic compound that exerts a wide range of beneficial effects, acting as an antimicrobial, antioxidant, anti-inflammatory and anticancer agent. This review summarizes recent data on curcumin’s ability to interfere with the multiple cell signaling pathways involved in cell cycle regulation, apoptosis and the migration of several cancer cell types. However, although curcumin displays anticancer potential, its clinical application is limited by its low absorption, rapid metabolism and poor bioavailability. To overcome these limitations, several curcumin-based derivatives/analogues and different drug delivery approaches have been developed. Here, we also report the anticancer mechanisms and pharmacokinetic characteristics of some derivatives/analogues and the delivery systems used. These strategies, although encouraging, require additional in vivo studies to support curcumin clinical applications.

scholarly journals Hemojuvelin regulates hepcidin expression via a selective subset of BMP ligands and receptors independently of neogenin

Blood ◽  
2008 ◽  
Vol 111 (10) ◽  
pp. 5195-5204 ◽  
Author(s):  
Yin Xia ◽  
Jodie L. Babitt ◽  
Yisrael Sidis ◽  
Raymond T. Chung ◽  
Herbert Y. Lin
Keyword(s):  
Iron Metabolism ◽  
Human Liver ◽  
Bmp Signaling ◽  
Type I ◽  
Type Ii ◽  
Hepcidin Expression ◽  
Bmp Receptors ◽  
Distinct Subset ◽  
Morphogenetic Protein

Abstract Hemojuvelin (HJV) is a coreceptor for bone morphogenetic protein (BMP) signaling that regulates hepcidin expression and iron metabolism. However, the precise combinations of BMP ligands and receptors used by HJV remain unknown. HJV has also been demonstrated to bind to neogenin, but it is not known whether this interaction has a role in regulating hepcidin expression. In the present study, we show that BMP-2, BMP-4, and BMP-6 are endogenous ligands for HJV in hepatoma-derived cell lines, and that all 3 of these ligands are expressed in human liver. We demonstrate in vitro that HJV selectively uses the BMP type II receptors ActRIIA and BMPRII, but not ActRIIB, and HJV enhances utilization of ActRIIA by BMP-2 and BMP-4. Interestingly, ActRIIA is the predominant BMP type II receptor expressed in human liver. While HJV can use all 3 BMP type I receptors (ALK2, ALK3, and ALK6) in vitro, only ALK2 and ALK3 are detected in human liver. Finally, we show that HJV-induced BMP signaling and hepcidin expression are not altered by neogenin overexpression or by inhibition of endogenous neogenin expression. Thus, HJV-mediated BMP signaling and hepcidin regulation occur via a distinct subset of BMP ligands and BMP receptors, independently of neogenin.

scholarly journals Dissecting BMP signaling input into the gene regulatory networks driving specification of the blood stem cell lineage

2017 ◽  
Vol 114 (23) ◽  
pp. 5814-5821 ◽  
Author(s):  
Arif Kirmizitas ◽  
Stuart Meiklejohn ◽  
Aldo Ciau-Uitz ◽  
Rachel Stephenson ◽  
Roger Patient
Keyword(s):  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Cell Lineage ◽  
Bmp Signaling ◽  
Hematopoietic Stem ◽  
Bmp Receptors ◽  
Stem Cell Lineage ◽  
Morphogenetic Protein ◽  
Gene Regulatory ◽  
Endothelial Genes

Hematopoietic stem cells (HSCs) that sustain lifelong blood production are created during embryogenesis. They emerge from a specialized endothelial population, termed hemogenic endothelium (HE), located in the ventral wall of the dorsal aorta (DA). In Xenopus, we have been studying the gene regulatory networks (GRNs) required for the formation of HSCs, and critically found that the hemogenic potential is defined at an earlier time point when precursors to the DA express hematopoietic as well as endothelial genes, in the definitive hemangioblasts (DHs). The GRN for DH programming has been constructed and, here, we show that bone morphogenetic protein (BMP) signaling is essential for the initiation of this GRN. BMP2, -4, and -7 are the principal ligands expressed in the lineage forming the HE. To investigate the requirement and timing of all BMP signaling in HSC ontogeny, we have used a transgenic line, which inducibly expresses an inhibitor of BMP signaling, Noggin, as well as a chemical inhibitor of BMP receptors, DMH1, and described the inputs from BMP signaling into the DH GRN and the HE, as well as into primitive hematopoiesis. BMP signaling is required in at least three points in DH programming: first to initiate the DH GRN through gata2 expression, then for kdr expression to enable the DH to respond to vascular endothelial growth factor A (VEGFA) ligand from the somites, and finally for gata2 expression in the DA, but is dispensable for HE specification after hemangioblasts have been formed.

scholarly journals Biophysical basis of the phase response curve of subthalamic neurons with generalization to other cell types

2012 ◽  
Vol 108 (7) ◽  
pp. 1838-1855 ◽  
Author(s):  
Michael A. Farries ◽  
Charles J. Wilson
Keyword(s):  
Phase Response Curve ◽  
Cell Types ◽  
Phase Response ◽  
Biophysical Model ◽  
Charge Redistribution ◽  
Response Curves ◽  
Wide Range ◽  
Voltage Dependent ◽  
The Difference ◽  
Subthalamic Neurons

Experimental evidence indicates that the response of subthalamic neurons to excitatory postsynaptic potentials (EPSPs) is well described by their infinitesimal phase response curves (iPRC). However, the factors controlling the shape of that iPRC, and hence controlling the way subthalamic neurons respond to synaptic input, are unclear. We developed a biophysical model of subthalamic neurons to aid in the understanding of their iPRCs; this model exhibited an iPRC type common to many subthalamic cells. We devised a method for deriving its iPRC from its biophysical properties that clarifies how these different properties interact to shape the iPRC. This method revealed why the response of subthalamic neurons is well approximated by their iPRCs and how that approximation becomes less accurate under strong fluctuating input currents. It also connected iPRC structure to aspects of cellular physiology that could be estimated in simple current-clamp experiments. This allowed us to directly compare the iPRC predicted by our theory with the iPRC estimated from the response to EPSPs or current pulses in individual cells. We found that theoretically predicted iPRCs agreed well with estimates derived from synaptic stimuli, but not with those estimated from the response to somatic current injection. The difference between synaptic currents and those applied experimentally at the soma may arise from differences in the dynamics of charge redistribution on the dendrites and axon. Ultimately, our approach allowed us to identify novel ways in which voltage-dependent conductances interact with AHP conductances to influence synaptic integration that will apply to a wide range of cell types.

scholarly journals Bone Morphogenetic Protein Signaling Is Required for Maintenance of Differentiated Phenotype, Control of Proliferation, and Hypertrophy in Chondrocytes

1998 ◽  
Vol 140 (2) ◽  
pp. 409-418 ◽  
Author(s):  
Motomi Enomoto-Iwamoto ◽  
Masahiro Iwamoto ◽  
Yoshiki Mukudai ◽  
Yasuhiko Kawakami ◽  
Tsutomu Nohno ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alkaline Phosphatase ◽  
Bone Morphogenetic Protein ◽  
Bmp Signaling ◽  
Collagen Gene ◽  
Type Ii ◽  
Type X Collagen ◽  
Bmp Receptors ◽  
Collagen Gene Expression ◽  
Morphogenetic Protein

To examine the role of bone morphogenetic protein (BMP) signaling in chondrocytes during endochondral ossification, the dominant negative (DN) forms of BMP receptors were introduced into immature and mature chondrocytes isolated from lower and upper portions of chick embryo sternum, respectively. We found that control sternal chondrocyte populations expressed type IA, IB, and II BMP receptors as well as BMP-4 and -7. Expression of a DN-type II BMP receptor (termed DN-BMPR-II) in immature lower sternal (LS) chondrocytes led to a loss of differentiated functions; compared with control cells, the DN-BMPR- II–expressing LS chondrocytes proliferated more rapidly, acquired a fibroblastic morphology, showed little expression of type II collagen and aggrecan genes, and upregulated type I collagen gene expression. Expression of DN-BMPR-II in mature hypertrophic upper sternal (US) chondrocytes caused similar effects. In addition, the DN-BMPR-II–expressing US cells exhibited little alkaline phosphatase activity and type X collagen gene expression, while the control US cells produced both alkaline phosphatase and type X collagen. Both DN-BMPR-II–expressing US and LS chondrocytes failed to respond to treatment with BMP-2 . When we examined the effects of DN forms of types IA and IB BMP receptors, we found that DN-BMPR-IA had little effect, while DN-BMPR-IB had similar but weaker effects compared with those of DN-BMPR-II. We conclude that BMP signaling, particularly that mediated by the type II BMP receptor, is required for maintenance of the differentiated phenotype, control of cell proliferation, and expression of hypertrophic phenotype.

scholarly journals Ecdysone signaling promotes expression of multifunctional RNA binding proteins essential for ovarian germline stem cell self-renewal in Drosophila

2018 ◽  
Author(s):  
Danielle S. Finger ◽  
Vivian V. Holt ◽  
Elizabeth T. Ables
Keyword(s):  
Stem Cell ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Bmp Signaling ◽  
Germline Stem Cell ◽  
Self Renewal ◽  
Bmp Receptors ◽  
Morphogenetic Protein ◽  
Ecdysone Signaling

ABSTRACTSteroid hormones promote stem cell self-renewal in many tissues; however, the molecular mechanisms by which hormone signaling is integrated with niche-derived signals are largely uncharacterized. In the Drosophila ovary, the steroid hormone ecdysone promotes germline stem cell (GSC) self-renewal. Despite strong evidence that ecdysone modulates the reception of bone morphogenetic protein (BMP) signals in GSCs, transcriptional targets of ecdysone signaling that facilitate BMP reception are unknown. Here, we report that ecdysone signaling promotes the expression of the heterogeneous nuclear ribonucleoproteins (hnRNPs) squid, hephaestus, Hrb27C, and Hrb87F in GSCs. These hnRNPs functionally interact with ecdysone signaling to control GSC number and are cell autonomously required in GSCs for their maintenance. We demonstrate that hnRNPs promote GSC self-renewal by binding to transcripts essential for proper BMP signaling, including the BMP receptors thickveins and punt. Our findings support the model that stem cells coordinate local and long-range signals at the transcriptional and post-transcriptional levels to maintain self-renewal in response to physiological demand.GRAPHICAL ABSTRACTEcdysone signaling regulates distinct hnRNPs that bind to BMP signaling targets to control GSC self-renewal.SUMMARY STATEMENTEcdysone signaling promotes expression of heterogeneous ribonucleoproteins that modulate BMP-dependent germline stem cell self-renewal in the Drosophila ovary.

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