scholarly journals CD13/APN regulates endothelial invasion and filopodia formation

Blood ◽  
2007 ◽  
Vol 110 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Nenad Petrovic ◽  
Wolfgang Schacke ◽  
J. Reed Gahagan ◽  
Catherine A. O'Conor ◽  
Beata Winnicka ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Endothelial Cell ◽  
Cell Motility ◽  
Receptor Internalization ◽  
Peptidase Activity ◽  
Protein Distribution ◽  
Wild Type ◽  
Serum Peptide ◽  
Exogenous Expression

CD13/aminopeptidase N is a transmembrane peptidase that is induced in the vasculature of solid tumors and is a potent angiogenic regulator. Here, we demonstrate that CD13 controls endothelial cell invasion in response to the serum peptide bradykinin by facilitating signal transduction at the level of the plasma membrane. Inhibition of CD13 abrogates bradykinin B2 receptor internalization, leading to the attenuation of downstream events such as bradykinin-induced activation of Cdc42 and filopodia formation, and thus affects endothelial cell motility. Investigation into mechanisms underlying this block led us to focus on B2R internalization via membrane-dependent mechanisms. Membrane disruption by depletion of cholesterol or trypsinization halts B2R internalization, invasion, and filopodia formation, which can be recovered with addition of cholesterol. However, this functional recovery is severely impaired in the presence of CD13 antagonists, and the distribution of membrane proteins is disordered in treated cells, suggesting a role for CD13 in plasma membrane protein organization. Finally, exogenous expression of wild-type but not mutant CD13 further alters protein distribution, suggesting peptidase activity is required for CD13's regulatory activity. Therefore, CD13 functions as a novel modulator of signal transduction and cell motility via its influence on specific plasma membrane organization, thus regulating angiogenesis.

Distinct roles of PMCA isoforms in Ca2+ homeostasis of bladder smooth muscle: evidence from PMCA gene-ablated mice

2007 ◽  
Vol 292 (1) ◽  
pp. C423-C431 ◽  
Author(s):  
Li Liu ◽  
Yukisato Ishida ◽  
Gbolahan Okunade ◽  
Gail J. Pyne-Geithman ◽  
Gary E. Shull ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Smooth Muscle ◽  
Plasma Membrane ◽  
Contractile Response ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Wild Type ◽  
Bladder Smooth Muscle

We previously showed that plasma membrane Ca2+-ATPase (PMCA) activity accounted for 25–30% of relaxation in bladder smooth muscle ( 8 ). Among the four PMCA isoforms only PMCA1 and PMCA4 are expressed in smooth muscle. To address the role of these isoforms, we measured cytosolic Ca2+ ([Ca2+]i) using fura-PE3 and simultaneously measured contractility in bladder smooth muscle from wild-type (WT), Pmca1+/−, Pmca4+/−, Pmca4−/−, and Pmca1+/− Pmca4−/− mice. There were no differences in basal [Ca2+]i values between bladder preparations. KCl (80 mM) elicited both larger forces (150–190%) and increases in [Ca2+]i (130–180%) in smooth muscle from Pmca1+/− and Pmca1+/− Pmca4−/− bladders than those in WT or Pmca4−/−. The responses to carbachol (CCh: 10 μM) were also greater in Pmca1+/− (120–150%) than in WT bladders. In contrast, the responses in Pmca4−/− and Pmca1+/− Pmca4−/− bladders to CCh were significantly smaller (40–50%) than WT. The rise in half-times of force and [Ca2+]i increases in response to KCl and CCh, and the concomitant half-times of their decrease upon washout of agonist were prolonged in Pmca4−/− (130–190%) and Pmca1+/− Pmca4−/− (120–250%) bladders, but not in Pmca1+/− bladders with respect to WT. Our evidence indicates distinct isoform functions with the PMCA1 isoform involved in overall Ca2+ clearance, while PMCA4 is essential for the [Ca2+]i increase and contractile response to the CCh receptor-mediated signal transduction pathway.

scholarly journals Oxidized glutathione decreases luminal Ca2+ content of the endothelial cell ins(1,4,5)P3-sensitive Ca2+ store

1995 ◽  
Vol 312 (2) ◽  
pp. 485-489 ◽  
Author(s):  
P N Henschke ◽  
S J Elliott
Keyword(s):  
Signal Transduction ◽  
Endothelial Cells ◽  
Plasma Membrane ◽  
Endothelial Cell ◽  
Pulmonary Artery ◽  
Vascular Tissue ◽  
Oxidant Stress ◽  
Inhibitory Effect ◽  
Oxidized Glutathione ◽  
Intact Cells

The model oxidant, t-butyl hydroperoxide (t-buOOH), inhibits Ins(1,4,5)P3-dependent Ca2+ signalling in calf pulmonary artery endothelial cells. Metabolism of t-buOOH within the cytosol is coupled to the oxidation of glutathione. In this study, we investigated whether oxidized glutathione (GSSG) is the intracellular moiety responsible for mediating the effects of t-buOOH on Ca2+ signalling. The increase in cytosolic [Ca2+] stimulated by application of 2,5-di-t-butylhydroquinone (BHQ) was used to estimate the luminal Ca2+ content of the Ins(1,4,5)P3-sensitive store in intact cells. Luminal Ca2+ content was unaffected by t-buOOH (0.4 mM, 0-3 h) unless intracellular GSSG content was concomitantly elevated. The effect was specific for increased GSSG and was not replicated by depletion of GSH. These results suggest that cytosolic GSSG, produced endogenously within the endothelial cell, decreases the luminal Ca2+ content of Ins(1,4,5)P3-sensitive Ca2+ stores. Depletion of internal Ca2+ stores by GSSG may represent a key mechanism by which some forms of oxidant stress inhibit signal transduction in vascular tissue. At the plasma membrane, t-buOOH is known to inhibit the capacitative Ca2+ influx pathway. Increased intracellular GSSG potentiated the inhibitory effect of t-buOOH on Ca2+ influx, thereby providing the first evidence that activity of the capacitative Ca2+ influx channel is sensitive to thiol reagents formed endogenously within the cell.

Role of immunoreceptor tyrosine-based inhibitory motifs of PECAM-1 in PECAM-1-dependent cell migration

2004 ◽  
Vol 287 (4) ◽  
pp. C1103-C1113 ◽  
Author(s):  
Christopher D. O’Brien ◽  
Gaoyuan Cao ◽  
Antonis Makrigiannakis ◽  
Horace M. DeLisser
Keyword(s):  
Cell Migration ◽  
Endothelial Cell ◽  
Cell Motility ◽  
Tyrosine Phosphatase ◽  
Focal Adhesions ◽  
Intercellular Junctions ◽  
Wild Type ◽  
Tyrosine Residues

Platelet endothelial cell adhesion molecule (PECAM-1), a transmembrane glycoprotein, has been implicated in angiogenesis, with recent evidence indicating the involvement of PECAM-1 in endothelial cell motility. The cytoplasmic domain of PECAM-1 contains two tyrosine residues, Y663 and Y686, that each fall within an immunoreceptor tyrosine-based inhibitory motif (ITIM). When phosphorylated, these residues together mediate the binding of the protein tyrosine phosphatase SHP-2. Because SHP-2 has been shown to be involved in the turnover of focal adhesions, a phenomenon required for efficient cell motility, the association of this phosphatase with PECAM-1 via its ITIMs may represent a mechanism by which PECAM-1 might facilitate cell migration. Studies were therefore done with cell transfectants expressing wild-type PECAM or mutant PECAM-1 in which residues Y663 and Y686 were mutated. These mutations eliminated PECAM-1 tyrosine phosphorylation and the association of PECAM-1 with SHP-2 but did not impair the ability of the molecule to localize at intercellular junctions or to bind homophilically. However, in vitro cell motility and tube formation stimulated by the expression of wild-type PECAM-1 were abrogated by the mutation of these tyrosine residues. Importantly, during wound-induced migration, the number of focal adhesions as well as the level of tyrosine phosphorylated paxillin detected in cells expressing wild-type PECAM-1 were markedly reduced compared with control cells or transfectants with mutant PECAM-1. These data suggest that, in vivo, the binding of SHP-2 to PECAM-1, via PECAM-1’s ITIM domains, promotes the turnover of focal adhesions and, hence, endothelial cell motility.

Cleavage of Arpin by Calpain as a Potential Regulation Mechanism of the Arp2/3 Complex and Cell Motility

2018 ◽  
Author(s):  
Renee Potashner
Keyword(s):  
Plasma Membrane ◽  
Cell Motility ◽  
Cancer Metastasis ◽  
Competitive Inhibition ◽  
Cell Movement ◽  
Personal Communication ◽  
Cysteine Proteases ◽  
Regulation Mechanism ◽  
Wild Type ◽  
In The Wild

Cell movement is mediated by cycles of actin polymerisation. A novel protein, Arpin, was discovered that has been suggested to decrease cell motility through competitive inhibition of WASP family proteins, the activators of the complex driving actin polymerisation. In preliminary studies, Arpin was found to inhibit the Arp2/3 complex (Gautreau and Blanchoin, personal communication). Arpin contains sequence homology to the Arp2/3-binding site of WASP proteins. Calpains, a family of intracellular calcium-dependent cysteine proteases, can be found near the plasma membrane and the concentration of calcium ion required for activation is decreased when calpain is bound to the plasma membrane in the presence of phospholipids (Leloup et al. 2010). The common localization of calpain and Arpin, along with the known contributions calpain has in regulating other cell motility proteins, makes calpain a likely candidate for Arpin regulation. By transfecting calpain wild-type (pz/pz), knockdown (p/p) and lentivirus rescue mouse embryonic fibroblasts with a plasmid containing the Arpin gene (c15orf38), I hope to show the presence of differential cleavage of Arpin by calpain in the wild-type cells compared to the calpain knock-down cells through Western blot analysis. Understanding how Arpin is regulated will provide a basis for further research in cell motility, which has contributions to cancer metastasis and other diseases.  

An Ultrastructural Study of Pericytes

1968 ◽  
Vol 26 ◽  
pp. 66-67
Author(s):  
T. M. Murad ◽  
E. von Haam
Keyword(s):  
Plasma Membrane ◽  
Endothelial Cell ◽  
Basement Membrane ◽  
Blood Vessel ◽  
Vascular Endothelial Cells ◽  
Myoepithelial Cells ◽  
Capillary Blood ◽  
The Body ◽  
Capillary Blood Vessel ◽  
Outer Plasma Membrane

Pericytes are vascular satellites present around capillary blood vessels and small venules. They have been observed in almost every tissue of the body and are thought to be related to vascular smooth muscle cells. Morphologically pericytes have great similarity to vascular endothelial cells and also slightly resemble myoepithelial cells.The present study describes the ultrastructural morphology of pericytes in normal breast tissue and in benign tumor of the breast. The study showed that pericytes are ovoid or elongated cells separated from the endothelial cell of the capillary blood vessel by the basement membrane of endothelial cell. The nuclei of pericytes are often very distinctive. Although some are round, oval, or elongated, others show marked irregularity and infolding of the nuclear membrane. The cytoplasm shows mono-or bipolar extension in which the cytoplasmic organelles are located (Fig. 1). These cytoplasmic extensions embrace the capillary blood vessel incompletely. The plasma membrane exhibits multiple areas of focal condensation called hemidesmosomes (Fig. 2, arrow). A variable number of pinocytotic vesicles are frequently seen lining the outer plasma membrane. Normally pericytes are surrounded by a basement membrane which is found more consistently on the outer plasma membrane separating the pericytes from the stromal connective tissue.

scholarly journals FixJ family regulator AcfR of Azorhizobium caulinodans is involved in symbiosis with the host plant

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wei Liu ◽  
Xue Bai ◽  
Yan Li ◽  
Haikun Zhang ◽  
Xiaoke Hu
Keyword(s):  
Signal Transduction ◽  
Host Plant ◽  
Type Strain ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Azorhizobium Caulinodans ◽  
Wild Type ◽  
Response Regulators ◽  
Free Living ◽  
Two Component

Abstract Background A wide variety of bacterial adaptative responses to environmental conditions are mediated by signal transduction pathways. Two-component signal transduction systems are one of the predominant means used by bacteria to sense the signals of the host plant and adjust their interaction behaviour. A total of seven open reading frames have been identified as putative two-component response regulators in the gram-negative nitrogen-fixing bacteria Azorhizobium caulinodans ORS571. However, the biological functions of these response regulators in the symbiotic interactions between A. caulinodans ORS571 and the host plant Sesbania rostrata have not been elucidated to date. Results In this study, we identified and investigated a two-component response regulator, AcfR, with a phosphorylatable N-terminal REC (receiver) domain and a C-terminal HTH (helix-turn-helix) LuxR DNA-binding domain in A. caulinodans ORS571. Phylogenetic analysis showed that AcfR possessed close evolutionary relationships with NarL/FixJ family regulators. In addition, six histidine kinases containing HATPase_c and HisKA domains were predicted to interact with AcfR. Furthermore, the biological function of AcfR in free-living and symbiotic conditions was elucidated by comparing the wild-type strain and the ΔacfR mutant strain. In the free-living state, the cell motility behaviour and exopolysaccharide production of the ΔacfR mutant were significantly reduced compared to those of the wild-type strain. In the symbiotic state, the ΔacfR mutant showed a competitive nodule defect on the stems and roots of the host plant, suggesting that AcfR can provide A. caulinodans with an effective competitive ability for symbiotic nodulation. Conclusions Our results showed that AcfR, as a response regulator, regulates numerous phenotypes of A. caulinodans under the free-living conditions and in symbiosis with the host plant. The results of this study help to elucidate the involvement of a REC + HTH_LuxR two-component response regulator in the Rhizobium-host plant interaction.

scholarly journals Mating in Saccharomyces cerevisiae: The Role of the Pheromone Signal Transduction Pathway in the Chemotropic Response to Pheromone

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Kathrin Schrick ◽  
Barbara Garvik ◽  
Leland H Hartwell
Keyword(s):  
Signal Transduction ◽  
Map Kinase ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Wild Type ◽  
Mating Partner ◽  
Map Kinase Cascade ◽  
Kinase Cascade ◽  
Wild Type Control

Abstract The mating process in yeast has two distinct aspects. One is the induction and activation of proteins required for cell fusion in response to a pheromone signal; the other is chemotropism, i.e., detection of a pheromone gradient and construction of a fusion site available to the signaling cell. To determine whether components of the signal transduction pathway necessary for transcriptional activation also play a role in chemotropism, we examined strains with null mutations in components of the signal transduction pathway for diploid formation, prezygote formation and the chemotropic process of mating partner discrimination when transcription was induced downstream of the mutation. Cells mutant for components of the mitogen-activated protein (MAP) kinase cascade (ste5, ste20, ste11, ste7 or fus3 kss1) formed diploids at a frequency 1% that of the wild-type control, but formed prezygotes as efficiently as the wild-type control and showed good mating partner discrimination, suggesting that the MAP kinase cascade is not essential for chemotropism. In contrast, cells mutant for the receptor (ste2) or the β or γ subunit (ste4 and stel8) of the G protein were extremely defective in both diploid and prezygote formation and discriminated poorly between signaling and nonsignaling mating partners, implying that these components are important for chemotropism.

scholarly journals Low ABA concentration promotes root growth and hydrotropism through relief of ABA INSENSITIVE 1-mediated inhibition of plasma membrane H+-ATPase 2

2021 ◽  
Vol 7 (12) ◽  
pp. eabd4113
Author(s):  
Rui Miao ◽  
Wei Yuan ◽  
Yue Wang ◽  
Irene Garcia-Maquilon ◽  
Xiaolin Dang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Root Growth ◽  
Experimental System ◽  
Aba Signaling ◽  
Wild Type ◽  
Normal Medium ◽  
C Terminus ◽  
Quadruple Mutant ◽  
Aba Insensitive ◽  
Aba Receptors

The hab1-1abi1-2abi2-2pp2ca-1 quadruple mutant (Qabi2-2) seedlings lacking key negative regulators of ABA signaling, namely, clade A protein phosphatases type 2C (PP2Cs), show more apoplastic H+ efflux in roots and display an enhanced root growth under normal medium or water stress medium compared to the wild type. The presence of low ABA concentration (0.1 micromolar), inhibiting PP2C activity via monomeric ABA receptors, enhances root apoplastic H+ efflux and growth of the wild type, resembling the Qabi2-2 phenotype in normal medium. Qabi2-2 seedlings also demonstrate increased hydrotropism compared to the wild type in obliquely-oriented hydrotropic experimental system, and asymmetric H+ efflux in root elongation zone is crucial for root hydrotropism. Moreover, we reveal that Arabidopsis ABA-insensitive 1, a key PP2C in ABA signaling, interacts directly with the C terminus of Arabidopsis plasma membrane H+-dependent adenosine triphosphatase 2 (AHA2) and dephosphorylates its penultimate threonine residue (Thr947), whose dephosphorylation negatively regulates AHA2.

scholarly journals Plant Hormone Metabolome and Transcriptome Analysis of Dwarf and Wild-type Banana

2021 ◽  
Author(s):  
Biao Deng ◽  
Xuan Wang ◽  
Xing Long ◽  
Ren Fang ◽  
Shuangyun Zhou ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Transcriptome Analysis ◽  
Regulatory Mechanism ◽  
Feedback Regulation ◽  
Wild Type ◽  
Hormone Levels ◽  
Transporter Protein ◽  
Repressor Proteins ◽  
Differential Gene ◽  
The Relationship

AbstractGibberellin (GA), auxin (IAA) and brassinosteroid (BR) are indispensable in the process of plant growth and development. Currently, research on the regulatory mechanism of phytohormones in banana dwarfism is mainly focused on GA, and few studies are focused on IAA and BR. In this study, we measured the contents of endogenous GA, IAA and BR and compared the transcriptomes of wild-type Williams banana and its dwarf mutant across five successive growth periods. We investigated the relationship between hormones and banana dwarfism and explored differential gene expression through transcriptome analysis, thus revealing the possible metabolic regulatory mechanism. We inferred a complex regulatory network of banana dwarfing. In terms of endogenous hormone levels, GA and IAA had significant effects on banana dwarfing, while BR had little effect. The key gene in GA biosynthesis of is GA2ox, and the key genes in IAA biosynthesis are TDC and YUCCA. The differential expression of these genes might be the main factor affecting hormone levels and plant height. In terms of hormone signal transduction, DELLA and AUX/IAA repressor proteins were the core regulators of GA and IAA, respectively. They inhibited the process of signal transduction and had feedback regulation on hormone levels. Finally, the transporter protein PIN, AUX1/LAX protein family and ABCB subfamily played supplementary roles in the transport of IAA. These results provide new insights into GA and IAA regulation of banana growth and a reliable foundation for the improvement of dwarf varieties.

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