scholarly journals Biophysical principles of choanoflagellate self-organization

2019 ◽  
Author(s):  
Ben T. Larson ◽  
Teresa Ruiz-Herrero ◽  
Stacey Lee ◽  
Sanjay Kumar ◽  
L. Mahadevan ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Biology ◽  
Early Stage ◽  
Self Organization ◽  
Proliferating Cells ◽  
Cell Lineages ◽  
Biophysical Processes ◽  
Salpingoeca Rosetta ◽  
Shed Light

AbstractInspired by the patterns of multicellularity in choanoflagellates, the closest living relatives of animals, we quantify the biophysical processes underlying the morphogenesis of rosette colonies in the choanoflagellateSalpingoeca rosetta. We find that rosettes reproducibly transition from an early stage of 2D growth to a later stage of 3D growth, despite the underlying stochasticity of the cell lineages. We postulate that the extracellular matrix (ECM) exerts a physical constraint on the packing of proliferating cells, thereby sculpting rosette morphogenesis. Our perturbative experiments coupled with biophysical simulations demonstrates the fundamental importance of a basally-secreted ECM for rosette morphogenesis. In addition, this yields a morphospace for the shapes of these multicellular colonies, consistent with observations of a range of choanoflagellates. Overall, our biophysical perspective on rosette development complements previous genetic perspectives and thus helps illuminate the interplay between cell biology and physics in regulating morphogenesis.Significance statementComparisons among animals and their closest living relatives, the choanoflagellates, have begun to shed light on the origin of animal multicellularity and development. Here we complement previous genetic perspectives on this process by focusing on the biophysical principles underlying colony morphology and morphogenesis. Our study reveals the crucial role of the extracellular matrix in shaping the colonies and leads to a phase diagram that delineates the range of morphologies as a function of the biophysical mechanisms at play.

scholarly journals Biophysical principles of choanoflagellate self-organization

2020 ◽  
Vol 117 (3) ◽  
pp. 1303-1311 ◽  
Author(s):  
Ben T. Larson ◽  
Teresa Ruiz-Herrero ◽  
Stacey Lee ◽  
Sanjay Kumar ◽  
L. Mahadevan ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Biology ◽  
Early Stage ◽  
Self Organization ◽  
Proliferating Cells ◽  
Cell Lineages ◽  
Biophysical Processes ◽  
Salpingoeca Rosetta ◽  
The Individual ◽  
Colony Shape

Inspired by the patterns of multicellularity in choanoflagellates, the closest living relatives of animals, we quantify the biophysical processes underlying the morphogenesis of rosette colonies in the choanoflagellate Salpingoeca rosetta. We find that rosettes reproducibly transition from an early stage of 2-dimensional (2D) growth to a later stage of 3D growth, despite the underlying variability of the cell lineages. Our perturbative experiments demonstrate the fundamental importance of a basally secreted extracellular matrix (ECM) for rosette morphogenesis and show that the interaction of the ECM with cells in the colony physically constrains the packing of proliferating cells and, thus, controls colony shape. Simulations of a biophysically inspired model that accounts for the size and shape of the individual cells, the fraction of ECM, and its stiffness relative to that of the cells suffices to explain our observations and yields a morphospace consistent with observations across a range of multicellular choanoflagellate colonies. Overall, our biophysical perspective on rosette development complements previous genetic perspectives and, thus, helps illuminate the interplay between cell biology and physics in regulating morphogenesis.

The role of geographical clusters in the success of reward-based crowdfunding campaigns

2020 ◽  
pp. 146575032091838
Author(s):  
Nunzia Carbonara
Keyword(s):  
Empirical Study ◽  
Early Stage ◽  
Entrepreneurial Activity ◽  
Common People ◽  
Data Set ◽  
Entrepreneurial Ventures ◽  
Small Investors ◽  
Shed Light ◽  
Geographical Clusters

Crowdfunding is a relatively new phenomenon, which disrupted the classic way to fund a venture. It consists in retrieving the capital needed to start an entrepreneurial activity drawing funds from a large base of small investors – generally common people – rather than from the traditional financial sources. Although many studies have been conducted on this topic, little focus has been put on the geography of this phenomenon. This article addresses this issue analysing whether regions characterized by the presence of geographical clusters are able to raise the probability of a successful crowdfunding campaign for projects located there. Drawing on a data set of 792 crowdfunded projects, we conduct an empirical study aimed at studying the role played by geographical clusters in fostering the crowdfunding of new entrepreneurial ventures. The results offer insights into the phenomenon of crowdfunding and shed light on the role of geographical clusters in the success of reward-based crowdfunding campaigns of early-stage entrepreneurial projects.

scholarly journals The role of spectrin in cell adhesion and cell–cell contact

2019 ◽  
Vol 244 (15) ◽  
pp. 1303-1312 ◽  
Author(s):  
Beata Machnicka ◽  
Renata Grochowalska ◽  
Dżamila M Bogusławska ◽  
Aleksander F Sikorski
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cell Surface ◽  
Cell Biology ◽  
Membrane Integrity ◽  
Cell Contact ◽  
Surface Activities ◽  
New Findings ◽  
Cell Cell

Spectrins are proteins that are responsible for many aspects of cell function and adaptation to changing environments. Primarily the spectrin-based membrane skeleton maintains cell membrane integrity and its mechanical properties, together with the cytoskeletal network a support cell shape. The occurrence of a variety of spectrin isoforms in diverse cellular environments indicates that it is a multifunctional protein involved in numerous physiological pathways. Participation of spectrin in cell–cell and cell–extracellular matrix adhesion and formation of dynamic plasma membrane protrusions and associated signaling events is a subject of interest for researchers in the fields of cell biology and molecular medicine. In this mini-review, we focus on data concerning the role of spectrins in cell surface activities such as adhesion, cell–cell contact, and invadosome formation. We discuss data on different adhesion proteins that directly or indirectly interact with spectrin repeats. New findings support the involvement of spectrin in cell adhesion and spreading, formation of lamellipodia, and also the participation in morphogenetic processes, such as eye development, oogenesis, and angiogenesis. Here, we review the role of spectrin in cell adhesion and cell–cell contact.Impact statementThis article reviews properties of spectrins as a group of proteins involved in cell surface activities such as, adhesion and cell–cell contact, and their contribution to morphogenesis. We show a new area of research and discuss the involvement of spectrin in regulation of cell–cell contact leading to immunological synapse formation and in shaping synapse architecture during myoblast fusion. Data indicate involvement of spectrins in adhesion and cell–cell or cell–extracellular matrix interactions and therefore in signaling pathways. There is evidence of spectrin’s contribution to the processes of morphogenesis which are connected to its interactions with adhesion molecules, membrane proteins (and perhaps lipids), and actin. Our aim was to highlight the essential role of spectrin in cell–cell contact and cell adhesion.

Cell Biology of Bladder Development and the Role of the Extracellular Matrix

2004 ◽  
Vol 95 (4) ◽  
pp. e129-e133 ◽  
Author(s):  
L.S.L. McCarthy ◽  
N. Smeulders ◽  
D.T. Wilcox
Keyword(s):  
Extracellular Matrix ◽  
Cell Biology

scholarly journals Proteoglycan IMPG2 shapes the interphotoreceptor matrix and modulates vision

2019 ◽  
Author(s):  
Ezequiel M Salido ◽  
Visvanathan Ramamurthy
Keyword(s):  
Extracellular Matrix ◽  
Vision Loss ◽  
Visual Deficits ◽  
Abnormal Accumulation ◽  
The Matrix ◽  
Photoreceptor Neurons ◽  
And Function ◽  
Interphotoreceptor Matrix ◽  
Shed Light

AbstractThe extracellular matrix surrounding the photoreceptor neurons, interphotoreceptor matrix (IPM) is comprised of two unique proteoglycans: IPM proteoglycan 1 and 2 (IMPG1 and IMPG2). Although the functions of the IPM are not understood, patients with mutations in IMPG1/2 develop visual deficits with subretinal material accumulation. Here, we generated mouse models lacking IMPG1/2 to decipher the role of these proteoglycans and the pathological mechanisms that lead to vision loss. IMPG1 and IMPG2 occupy specific locations in the outer retina, and both proteoglycans are fundamental for the constitution of the IPM system. Mice lacking IMPG2 show abnormal accumulation of IMPG1, and in later stages, develop subretinal lesions and reduced visual function. Interestingly, removal of IMPG1-2 showed normal retinal morphology and function, suggesting that the aberrant localization of IMPG1 causes the alterations observed in IMPG2 KO mice. In conclusion, our results demonstrate the role of IMPG2 in shaping the IPM, shed light on the potential mechanisms leading to subretinal lesions, and show that the secreted proteoglycans depend on the extracellular matrix environment to properly integrate into the matrix.

The role of the extracellular matrix in promoting early stage mycosis fungoides

2019 ◽  
Vol 119 ◽  
pp. S2-S3
Author(s):  
John Ringe ◽  
Sarah Baik ◽  
Pierluigi Porcu ◽  
Neda Nikbakht
Keyword(s):  
Extracellular Matrix ◽  
Mycosis Fungoides ◽  
Early Stage

scholarly journals The Role of Complement and the Extracellular Matrix in Early Stage Macular Degeneration

2015 ◽  
Vol 29 (S1) ◽  
Author(s):  
Rosario Fernandez‐Godino ◽  
Eric Pierce ◽  
Donita Garland
Keyword(s):  
Extracellular Matrix ◽  
Macular Degeneration ◽  
Early Stage

Extracellular ATP, a danger signal, is recognized by DORN1 in Arabidopsis

2014 ◽  
Vol 463 (3) ◽  
pp. 429-437 ◽  
Author(s):  
Jeongmin Choi ◽  
Kiwamu Tanaka ◽  
Yan Liang ◽  
Yangrong Cao ◽  
Sang Yeol Lee ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Stress Responses ◽  
Early Stage ◽  
Plant Stress ◽  
Extracellular Atp ◽  
Receptor Kinase ◽  
Danger Signal ◽  
Lectin Receptor ◽  
Plant Stress Responses

ATP, the universal energy currency of all organisms, is released into the extracellular matrix and serves as a signal among cells, where it is referred to as an extracellular ATP. Although a signalling role for extracellular ATP has been well studied in mammals over the last 40 years, investigations of such a role in plants are at an early stage. Recently, the first plant receptor for extracellular ATP, DOes not Respond to Nucleotides (DORN1), was identified in Arabidopsis thaliana by mutant screening. DORN1 encodes a legume-type lectin receptor kinase that is structurally distinct from the mammalian extracellular ATP receptors. In the present review, we highlight the genetic and biochemical evidence for the role of DORN1 in extracellular ATP signalling, placing this within the wider context of extracellular ATP signalling during plant stress responses.

scholarly journals Cardiac Differentiation of Human Pluripotent Stem Cells Using Defined Extracellular Matrix Proteins Reveals Essential Role of Fibronectin

2021 ◽  
Author(s):  
Jianhua Zhang ◽  
Ran Tao ◽  
Pratik A. Lalit ◽  
Juliana L Carvalho ◽  
Yogananda Markandeya ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Pluripotent Stem Cells ◽  
Essential Role ◽  
Early Stage ◽  
Cardiac Differentiation ◽  
Matrix Proteins ◽  
Downstream Signaling ◽  
Mesoderm Formation ◽  
Integrin Linked Kinase

Research and therapeutic applications using human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) require robust differentiation strategies. Efforts to improve hPSC-CM differentiation have largely overlooked the role of extracellular matrix (ECM). The present study investigates the ability of defined ECM proteins to promote hPSC cardiac differentiation. Fibronectin, laminin-111, and laminin-521 enabled hPSCs to attach and expand; however, fibronectin ECM either endogenously produced or exogenously added promoted, while laminins inhibited, cardiac differentiation in response to growth factors Activin A, BMP4, and bFGF. Inducible shRNA knockdown of fibronectin prevented Brachyury+ mesoderm formation and subsequent hPSC-CM differentiation. Antibodies blocking fibronectin binding to integrin β1, but not α5, inhibited cardiac differentiation. Furthermore, inhibition of integrin-linked kinase blocked cardiac differentiation. These results identify fibronectin, laminin-111 and laminin-521 as defined substrates enabling cardiac differentiation of hPSCs and uncover the essential role of fibronectin and downstream signaling pathways in the early stage of hPSC-CM differentiation.

The role of geographical clusters in the success of reward-based crowdfunding campaigns

2020 ◽  
Vol 21 (4) ◽  
pp. 250-262 ◽  
Author(s):  
Carbonara Nunzia
Keyword(s):  
Empirical Study ◽  
Early Stage ◽  
Geographical Area ◽  
Data Set ◽  
Entrepreneurial Ventures ◽  
Shed Light ◽  
Geographical Clusters

This article studies whether some salient characteristics of the geographical area in which a crowdfunding campaign is launched affect its success. Drawing on a data set of 792 crowdfunded projects, we conduct an empirical study aimed at studying the role played by geographical clusters (GCs) in fostering the crowdfunding of new entrepreneurial ventures. The results offer insights into the phenomenon of crowdfunding and shed light on the role of GCs in the success of reward-based crowdfunding campaigns of early-stage entrepreneurial projects.

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