scholarly journals Quantification of intracellular N-terminal β-actin arginylation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Li Chen ◽  
Anna Kashina
Keyword(s):  
Amino Acid Level ◽  
Leading Edge ◽  
State Level ◽  
Cell Types ◽  
Field Work ◽  
Physiological Conditions ◽  
Recent Interest ◽  
Migratory Cells ◽  
Dynamic Interplay

Abstract Actin is a ubiquitous, essential, and highly abundant protein in all eukaryotic cells that performs key roles in contractility, adhesion, migration, and leading edge dynamics. The two non-muscle actins, β- and γ-, are ubiquitously present in every cell type and are nearly identical to each other at the amino acid level, but play distinct intracellular roles. The mechanisms regulating this distinction have been the focus of recent interest in the field. Work from our lab has previously shown that β-, but not γ-, actin undergoes N-terminal arginylation on Asp3. While functional evidence suggest that this arginylation may be important to actin’s function, progress in these studies so far has been hindered by difficulties in arginylated actin detection, precluding estimations of the abundance of arginylated actin in cells, and its occurrence in different tissues and cell types. The present study represents the first antibody-based quantification of the percentage of arginylated actin in migratory non-muscle cells under different physiological conditions, as well as in different cells and tissues. We find that while the steady-state level of arginylated actin is relatively low, it is consistently present in vivo, and is somewhat more prominent in migratory cells. Inhibition of N-terminal actin acetylation dramatically increases the intracellular actin arginylation level, suggesting that these two modifications may directly compete in vivo. These findings constitute an essential step in our understanding of actin regulation by arginylation, and in uncovering the dynamic interplay of actin’s N-terminal modifications in vivo.

scholarly journals Cell division in two large pennate diatoms Hantzschia and Nitzschia III. A new proposal for kinetochore function during prometaphase.

1980 ◽  
Vol 86 (2) ◽  
pp. 402-416 ◽  
Author(s):  
D H Tippit ◽  
J D Pickett-Heaps ◽  
R Leslie
Keyword(s):  
Electron Microscopy ◽  
Leading Edge ◽  
Time Lapse ◽  
Cell Types ◽  
Spindle Pole ◽  
Large Species ◽  
Conventional View ◽  
Chromosome Movements ◽  
Kinetochore Function

Prometaphase in two large species of diatoms is examined, using the following techniques: (a) time-lapse cinematography of chromosome movements in vivo; (b) electron microscopy of corresponding stages: (c) reconstruction of the microtubules (MTs) in the kinetochore fiber of chromosomes attached to the spindle. In vivo, the chromosomes independently commence oscillations back and forth to one pole. The kinetochore is usually at the leading edge of such chromosome movements; a variable time later both kinetochores undergo such oscillations but toward opposite poles and soon stretch poleward to establish stable bipolar attachment. Electron microscopy of early prometaphase shows that the kinetochores usually laterally associate with MTs that have one end attached to the spindle pole. At late prometaphase, most chromosomes are fully attached to the spindle, but the kinetochores on unattached chromosomes are bare of MTs. Reconstruction of the kinetochore fiber demonstrates that most of its MTs (96%) extend past the kinetochore and are thus apparently not nucleated there. At least one MT terminates at each kinetochore analyzed. Our interpretation is that the conventional view of kinetochore function cannot apply to diatoms. The kinetochore fiber in diatoms appears to be primarily composed of MTs from the poles, in contrast to the conventional view that many MTs of the kinetochore fiber are nucleated by the kinetochore. Similarly, chromosomes appear to initially orient their kinetochores to opposite poles by moving along MTs attached to the poles, instead of orientation effected by kinetochore MTs laterally associating with other MTs in the spindle. The function of the kinetochore in diatoms and other cell types is discussed.

scholarly journals Age-associated telomere attrition of lymphocytes in vivo is co-ordinated with changes in telomerase activity, composition of lymphocyte subsets and health conditions

2014 ◽  
Vol 128 (6) ◽  
pp. 367-377 ◽  
Author(s):  
Yun Lin ◽  
Amanda Damjanovic ◽  
E. Jeffrey Metter ◽  
Huy Nguyen ◽  
Thai Truong ◽  
...  
Keyword(s):  
Lymphocyte Subsets ◽  
Length Change ◽  
Cell Types ◽  
Telomerase Activity ◽  
Health Conditions ◽  
Telomere Attrition ◽  
Physiological Conditions ◽  
Cell Percentage ◽  
Different Cell Types

The present longitudinal study reveals that the telomere length change with age in vivo differs among individuals and in different cell types and is influenced by telomerase activity, naïve T-cell percentage and changes in physiological conditions such as glucose and interleukin-6 levels.

Abstract 415: Role of Proteolysis in the Remodeling of High-Density Lipoprotein

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Shobini Jayaraman
Keyword(s):  
Western Blotting ◽  
Density Lipoprotein ◽  
Cell Types ◽  
Size Exclusion ◽  
Major Protein ◽  
Physiological Conditions ◽  
Hdl Functionality ◽  
Exclusion Chromatography ◽  
Arterial Intima

Introduction: Both quantity and quality of the circulating HDL determine their optimal anti-atherogenic potential. During atherogenesis, various cell types in the arterial intima release enzymes into the intimal fluid, which modify HDL proteins and lipids that adversely affect HDL functionality. Hypothesis: The emerging paradigm for the in vivo proteolytic inactivation of HDL is centered on pre-beta-HDL. Over 90% of the major HDL proteins, apoA-I and apoA-II, circulate on mature HDL. Although binding to HDL protects these proteins from proteolysis, such proteolysis cannot be completely excluded, and its effects on HDL functionality remain unknown. Methods: Human plasma HDL were subjected to mild proteolysis with plasmin, a protease active in atherosclerotic lesions. The proteolytic products were analyzed by SDS-PAGE and Western blotting. HDL remodeling was monitored under near-physiological conditions by size-exclusion chromatography and gel electrophoresis. Results: HDL treatment with plasmin caused no significant structural remodeling of lipoprotein particles. Interestingly, plasmin cleaved apoA-I and apoA-II on HDL. The major protein fragments were observed in the 10-12 kDa range. Western blotting indicated that these fragments were derived from both apoA-I and apoA-II. Next, intact and plasmin-treated HDL were incubated at 37 o C, pH 7.5 for 6-12 h. Intact HDL showed dissociation of a fraction of lipid-free apoA-I without significant changes in the particle size. In contrast, plasmin-treated HDL underwent fusion with release of full-length and fragmented apoA-I and apoA-II, indicating lipoprotein destabilization. Conclusion: Our results reveal that plasmin, can cleave HDL-bound forms of apoA-I and apoA-II and thereby destabilize HDL under near-physiological conditions, resulting in HDL disintegration and dissociation of lipid-free proteins. For the first time, we demonstrate that proteolysis can render not only lipid-free but also HDL-bound proteins dysfunctional. Destabilization of HDL via proteolytic modifications may contribute to the recently observed excessive accumulation of lipid-free apoA-I in the arterial intima, which probably contributes to the progression of atherosclerosis.

scholarly journals Protrusive waves guide 3D cell migration along nanofibers

2015 ◽  
Vol 211 (3) ◽  
pp. 683-701 ◽  
Author(s):  
Charlotte Guetta-Terrier ◽  
Pascale Monzo ◽  
Jie Zhu ◽  
Hongyan Long ◽  
Lakshmi Venkatraman ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Body ◽  
Three Dimensional ◽  
Leading Edge ◽  
Cell Types ◽  
Matrix Deformation ◽  
Directional Movement ◽  
Modeling Data ◽  
3D Cell Migration

In vivo, cells migrate on complex three-dimensional (3D) fibrous matrices, which has made investigation of the key molecular and physical mechanisms that drive cell migration difficult. Using reductionist approaches based on 3D electrospun fibers, we report for various cell types that single-cell migration along fibronectin-coated nanofibers is associated with lateral actin-based waves. These cyclical waves have a fin-like shape and propagate up to several hundred micrometers from the cell body, extending the leading edge and promoting highly persistent directional movement. Cells generate these waves through balanced activation of the Rac1/N-WASP/Arp2/3 and Rho/formins pathways. The waves originate from one major adhesion site at leading end of the cell body, which is linked through actomyosin contractility to another site at the back of the cell, allowing force generation, matrix deformation and cell translocation. By combining experimental and modeling data, we demonstrate that cell migration in a fibrous environment requires the formation and propagation of dynamic, actin based fin-like protrusions.

scholarly journals Adipokines in the Skin and in Dermatological Diseases

2020 ◽  
Vol 21 (23) ◽  
pp. 9048
Author(s):  
Dóra Kovács ◽  
Fruzsina Fazekas ◽  
Attila Oláh ◽  
Dániel Törőcsik
Keyword(s):  
Hair Growth ◽  
Inflammatory Diseases ◽  
Genetic Data ◽  
Serum Levels ◽  
Cell Types ◽  
Dermatological Diseases ◽  
Physiological Conditions ◽  
Acne Rosacea

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.

scholarly journals Two differentially expressed interleukin-11 receptor genes in the mouse genome

1996 ◽  
Vol 320 (2) ◽  
pp. 359-363 ◽  
Author(s):  
Petra BILINSKI ◽  
Mark A. HALL ◽  
Herbert NEUHAUS ◽  
Cornelia GISSEL ◽  
John K. HEATH ◽  
...  
Keyword(s):  
Mouse Genome ◽  
Amino Acid Level ◽  
Cell Types ◽  
Ligand Specificity ◽  
Gene Encoding ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Interleukin 11

Interleukin-11 (IL-11) is a multifunctional cytokine involved in the regulation of cell proliferation and differentiation in a variety of cell types and tissues in vitro and in vivo. The effects of IL-11 were shown to be mediated by the IL-11 receptor (hereafter referred to as IL-11Rα), which is a ligand-binding subunit and provides ligand specificity in a functional multimeric signal-transduction complex with gp130. Here we show that the mouse genome contains a second gene encoding an IL-11-binding protein, referred to as IL-11Rβ. The structure of the IL-11Rβ gene is highly similar to that of IL-11Rα, and IL-11Rβ exhibits 99% sequence identity with IL-11Rα at the amino acid level. IL-11Rβ is co-expressed with IL-11Rα, albeit at lower levels, in embryos and in various adult tissues. IL-11Rβ transcripts are abundant in testis, and, in contrast with IL-11Rα, absent from skeletal muscle. IL-11Rβ expressed in vitro binds IL-11 with high affinity, suggesting that the mouse genome contains a second functional IL-11R.

scholarly journals The Drosophila dysfusion Basic Helix-Loop-Helix (bHLH)-PAS Gene Controls Tracheal Fusion and Levels of the Trachealess bHLH-PAS Protein

2003 ◽  
Vol 23 (16) ◽  
pp. 5625-5637 ◽  
Author(s):  
Lan Jiang ◽  
Stephen T. Crews
Keyword(s):  
Leading Edge ◽  
Cell Types ◽  
Embryonic Cell ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Tracheal Cell ◽  
Cellular Events ◽  
Dorsal Branch ◽  
Protein Functions

ABSTRACT The development of the mature insect trachea requires a complex series of cellular events, including tracheal cell specification, cell migration, tubule branching, and tubule fusion. Here we describe the identification of the Drosophila melanogaster dysfusion gene, which encodes a novel basic helix-loop-helix (bHLH)-PAS protein conserved between Caenorhabditis elegans, insects, and humans, and controls tracheal fusion events. The Dysfusion protein functions as a heterodimer with the Tango bHLH-PAS protein in vivo to form a putative DNA-binding complex. The dysfusion gene is expressed in a variety of embryonic cell types, including tracheal-fusion, leading-edge, foregut atrium cells, nervous system, hindgut, and anal pad cells. RNAi experiments indicate that dysfusion is required for dorsal branch, lateral trunk, and ganglionic branch fusion but not for fusion of the dorsal trunk. The escargot gene, which is also expressed in fusion cells and is required for tracheal fusion, precedes dysfusion expression. Analysis of escargot mutants indicates a complex pattern of dysfusion regulation, such that dysfusion expression is dependent on escargot in the dorsal and ganglionic branches but not the dorsal trunk. Early in tracheal development, the Trachealess bHLH-PAS protein is present at uniformly high levels in all tracheal cells, but since the levels of Dysfusion rise in wild-type fusion cells, the levels of Trachealess in fusion cells decline. The downregulation of Trachealess is dependent on dysfusion function. These results suggest the possibility that competitive interactions between basic helix-loop-helix-PAS proteins (Dysfusion, Trachealess, and possibly Similar) may be important for the proper development of the trachea.

scholarly journals Clasp-mediated microtubule bundling regulates persistent motility and contact repulsion in Drosophila macrophages in vivo

2010 ◽  
Vol 189 (4) ◽  
pp. 681-689 ◽  
Author(s):  
Brian Stramer ◽  
Severina Moreira ◽  
Tom Millard ◽  
Iwan Evans ◽  
Chieh-Yin Huang ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
High Resolution ◽  
Fluorescent Probes ◽  
In Vivo Imaging ◽  
Living Organism ◽  
Developmental Guidance ◽  
Cytoskeletal Networks ◽  
Migratory Cells ◽  
Dynamic Interplay

Drosophila melanogaster macrophages are highly migratory cells that lend themselves beautifully to high resolution in vivo imaging experiments. By expressing fluorescent probes to reveal actin and microtubules, we can observe the dynamic interplay of these two cytoskeletal networks as macrophages migrate and interact with one another within a living organism. We show that before an episode of persistent motility, whether responding to developmental guidance or wound cues, macrophages assemble a polarized array of microtubules that bundle into a compass-like arm that appears to anticipate the direction of migration. Whenever cells collide with one another, their microtubule arms transiently align just before cell–cell repulsion, and we show that forcing depolymerization of microtubules by expression of Spastin leads to their defective polarity and failure to contact inhibit from one another. The same is true in orbit/clasp mutants, indicating a pivotal role for this microtubule-binding protein in the assembly and/or functioning of the microtubule arm during polarized migration and contact repulsion.

Effects of the substratum on the migration of primordial germ cells

1982 ◽  
Vol 299 (1095) ◽  
pp. 177-183 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Migration ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cell Types ◽  
Artificial Substrates ◽  
Transmission Electron ◽  
Migratory Cells

It is now clear from work on defined cell types on artificial substrates that various chemical and physical inhomogeneities in the substrates can guide cell locomotion. It is also becoming clear that less well defined inhomogeneities in living cell substrates can guide the normal locomotion of embryonic migratory cells in vivo. The primordial germ cells (p.g.cs) of early anuran amphibian embryos are proving a useful model for the study of cell migration. When isolated from the embryo and cultured on living cellular substrate, p.g.cs become oriented by the shapes of the underlying cells or by their stress fibre cytoskeleton, or both. A combination of scanning and transmission electron microscopy in vivo shows a clearly aligned cellular substrate for p.g.c. migration along part of their route. Furthermore, we find that the glycoprotein fibronectin is involved in p.g.c. adhesion, which suggests a link between orientation of the substrate cells and p.g.c. guidance.

scholarly journals E-cadherin focuses protrusion formation at the front of migrating cells by impeding actin flow

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Cecilia Grimaldi ◽  
Isabel Schumacher ◽  
Aleix Boquet-Pujadas ◽  
Katsiaryna Tarbashevich ◽  
Bart Eduard Vos ◽  
...  
Keyword(s):  
Primordial Germ Cells ◽  
Leading Edge ◽  
Cell Types ◽  
Restricted Area ◽  
Cell Front ◽  
Frictional Forces ◽  
Migrating Cells ◽  
E Cadherin

Abstract The migration of many cell types relies on the formation of actomyosin-dependent protrusions called blebs, but the mechanisms responsible for focusing this kind of protrusive activity to the cell front are largely unknown. Here, we employ zebrafish primordial germ cells (PGCs) as a model to study the role of cell-cell adhesion in bleb-driven single-cell migration in vivo. Utilizing a range of genetic, reverse genetic and mathematical tools, we define a previously unknown role for E-cadherin in confining bleb-type protrusions to the leading edge of the cell. We show that E-cadherin-mediated frictional forces impede the backwards flow of actomyosin-rich structures that define the domain where protrusions are preferentially generated. In this way, E-cadherin confines the bleb-forming region to a restricted area at the cell front and reinforces the front-rear axis of migrating cells. Accordingly, when E-cadherin activity is reduced, the bleb-forming area expands, thus compromising the directional persistence of the cells.

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