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.  

scholarly journals How Cysteine Protease Gene PtCP5 Affects Seed Germination by Mobilizing Storage Proteins in Populus trichocarpa

2021 ◽  
Vol 22 (23) ◽  
pp. 12637
Author(s):  
Xiatong Liu ◽  
Lijie Mo ◽  
Xiaorui Guo ◽  
Qiang Zhang ◽  
Hui Li ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Seed Germination ◽  
Cysteine Protease ◽  
Storage Proteins ◽  
Populus Trichocarpa ◽  
Cysteine Proteases ◽  
Protein Accumulation ◽  
Wild Type ◽  
Protein Storage Vacuoles ◽  
In The Wild

In higher plants, seed storage proteins are deposited in protein storage vacuoles (PSVs) and degraded by protease, especially cysteine proteases, as a source of nitrogen for seed germination. In this study, a cathepsin B-like cysteine protease PtCP5, which is important for seed germination and pollen development, was first cloned in Populus trichocarpa. The GUS staining of the ProPtCP5-GUS reporter line showed that PtCP5 is expressed in the roots, stems, leaves, flowers, siliques and seeds of Arabidopsis. We reveal that PtCP5 is present in plasma membrane and co-localizes with the plasma membrane marker REM1.3. Both seed germination and early seedling development are slower in OX-PtCP5 transgenic Arabidopsis when compared with the wild-type. Further analysis revealed that, when stained with toluidine blue, the observed storage protein accumulation was lower in OX-PtCP5 than in the wild-type. Our results also show that the number of abnormal pollen grains is higher and the germination rate of pollen is lower in OX-PtCP5 than in the wild-type. These results indicate that PtCP5 is an important factor in mobilizing storage proteins and that the proper expression of PtCP5 is necessary for both pollen and seed maturation and germination. This study sheds further light on the biological functions of cysteine proteases and provides further reference for seed development research on woody plants.

Modulation of frequency and height of cytosolic calcium spikes by plasma membrane anion channels in guard cells

2021 ◽  
Author(s):  
Md Tahjib-Ul-Arif ◽  
Shintaro Munemasa ◽  
Toshiyuki Nakamura ◽  
Yoshimasa Nakamura ◽  
Yoshiyuki Murata
Keyword(s):  
Plasma Membrane ◽  
Stomatal Closure ◽  
Anion Channel ◽  
Guard Cells ◽  
Cytosolic Calcium ◽  
Peak Height ◽  
Extracellular Calcium ◽  
Wild Type ◽  
Anion Channels ◽  
In The Wild

Abstract Cytosolic calcium ([Ca2+]cyt) elevation activates plasma membrane anion channels in guard cells, which is required for stomatal closure. However, involvement of the anion channels in the [Ca2+]cyt elevation remains unclear. We investigated the involvement using Arabidopsis thaliana anion channel mutants, slac1-4 slah3-3 and slac1-4 almt12-1. Extracellular calcium induced stomatal closure in the wild-type plants but not in the anion channel mutant plants whereas extracellular calcium induced [Ca2+]cyt elevation both in the wild-type guard cells and in the mutant guard cells. The peak height and the number of the [Ca2+]cyt spike were lower and larger in the slac1-4 slah3-3 than in the wild-type and the height and the number in the slac1-4 almt12-1 were much lower and much larger than in the wild-type. These results suggest that the anion channels are involved in the regulation of [Ca2+]cyt elevation in guard cells.

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.

scholarly journals Exomer Is Part of a Hub Where Polarized Secretion and Ionic Stress Connect

2021 ◽  
Vol 12 ◽  
Author(s):  
Sandra Moro ◽  
Esteban Moscoso-Romero ◽  
Abhishek Poddar ◽  
Jose M. Mulet ◽  
Pilar Perez ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Transient Receptor Potential ◽  
Ion Homeostasis ◽  
Wild Type ◽  
Plasma Membrane Atpase ◽  
General Role ◽  
Membrane Hyperpolarization ◽  
Polarized Secretion ◽  
In The Wild ◽  
Golgi Network

Plasma membrane and membranous organelles contribute to the physiology of the Eukaryotic cell by participating in vesicle trafficking and the maintenance of ion homeostasis. Exomer is a protein complex that facilitates vesicle transport from the trans-Golgi network to the plasma membrane, and its absence leads to the retention of a set of selected cargoes in this organelle. However, this retention does not explain all phenotypes observed in exomer mutants. The Schizosaccharomyces pombe exomer is composed of Cfr1 and Bch1, and cfr1Δ and bch1Δ were sensitive to high concentrations of potassium salts but not sorbitol, which showed sensitivity to ionic but not osmotic stress. Additionally, the activity of the plasma membrane ATPase was higher in exomer mutants than in the wild-type, pointing to membrane hyperpolarization, which caused an increase in intracellular K+ content and mild sensitivity to Na+, Ca2+, and the aminoglycoside antibiotic hygromycin B. Moreover, in response to K+ shock, the intracellular Ca2+ level of cfr1Δ cells increased significantly more than in the wild-type, likely due to the larger Ca2+ spikes in the mutant. Microscopy analyses showed a defective endosomal morphology in the mutants. This was accompanied by an increase in the intracellular pools of the K+ exporting P-type ATPase Cta3 and the plasma membrane Transient Receptor Potential (TRP)-like Ca2+ channel Pkd2, which were partially diverted from the trans-Golgi network to the prevacuolar endosome. Despite this, most Cta3 and Pkd2 were delivered to the plasma membrane at the cell growing sites, showing that their transport from the trans-Golgi network to the cell surface occurred in the absence of exomer. Nevertheless, shortly after gene expression in the presence of KCl, the polarized distribution of Cta3 and Pkd2 in the plasma membrane was disturbed in the mutants. Finally, the use of fluorescent probes suggested that the distribution and dynamics of association of some lipids to the plasma membrane in the presence of KCl were altered in the mutants. Thus, exomer participation in the response to K+ stress was multifaceted. These results supported the notion that exomer plays a general role in protein sorting at the trans-Golgi network and in polarized secretion, which is not always related to a function as a selective cargo adaptor.

scholarly journals IDH1 and IDH2 mutants identified in cancer lose inhibition by isocitrate because of a change in their binding sites

2018 ◽  
Author(s):  
Juan P. Bascur ◽  
Melissa Alegría-Arcos ◽  
Ingrid Araya-Durán ◽  
Ezequiel I. Juritz ◽  
Fernando D. González-Nilo ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Binding Sites ◽  
Competitive Inhibition ◽  
Binding Energies ◽  
Substrate Affinity ◽  
Wild Type ◽  
Similarity Estimation ◽  
In The Wild ◽  
Docking Calculations ◽  
Idh1 And Idh2 Mutations

AbstractIDH1 and IDH2 are human enzymes that convert isocitrate (ICT) into α-ketoglutarate (AKG). However, mutations in positions R132 of IDH1 and R140 and R172 of IDH2 cause these enzymes to convert AKG into 2-hydroxyglutarate (2HG). Concurrently, accumulation of 2HG in the cell is correlated with the development of cancer. This activity change is mainly due to the loss of the competitive inhibition by ICT of these enzymes, but the molecular mechanism behind this loss of inhibition is currently unknown. In this work we characterized the inhibition and loss of inhibition of IDH1 and IDH2 by means of the binding energies derived from molecular docking calculations. We characterized the substrate binding sites and how they differ among the mutant and wild type enzymes using a Jaccard similarity coefficient based on the residues involved in binding the substrates. We found that molecular docking effectively identifies the inhibition by ICT in the wild type and mutant enzymes that do not appear in tumors, and the loss of inhibition in the mutant enzymes that appear in tumors. Additionally, we found that the binding sites of the mutant enzymes are different among themselves. Finally, we found that the regulatory segment of IDH1 plays a prominent role in the change of binding sites between the mutant enzymes and the wild-type enzymes. Our findings show that the loss of inhibition is related to variations in the enzyme binding sites. Additionally, our findings show that a drug capable of targeting all IDH1 and IDH2 mutations in cancer is unlikely to be found due to significant differences among the binding sites of these paralogs. Moreover, the methodology developed here, which combines molecular docking calculations with binding site similarity estimation, can be useful for engineering enzymes, for instance, when aiming to modify the substrate affinity of an enzyme.

scholarly journals Phosphorylation of UT-A1 on serine 486 correlates with membrane accumulation and urea transport activity in both rat IMCDs and cultured cells

2010 ◽  
Vol 298 (4) ◽  
pp. F935-F940 ◽  
Author(s):  
Janet D. Klein ◽  
Mitsi A. Blount ◽  
Otto Fröhlich ◽  
Chad E. Denson ◽  
Xiaoxiao Tan ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Cell Lines ◽  
Specific Antibody ◽  
Cultured Cells ◽  
Apical Plasma Membrane ◽  
Wild Type ◽  
Amino Acid Peptide ◽  
In The Wild

Vasopressin is the primary hormone regulating urine-concentrating ability. Vasopressin phosphorylates the UT-A1 urea transporter in rat inner medullary collecting ducts (IMCDs). To assess the effect of UT-A1 phosphorylation at S486, we developed a phospho-specific antibody to S486-UT-A1 using an 11 amino acid peptide antigen starting from amino acid 482 that bracketed S486 in roughly the center of the sequence. We also developed two stably transfected mIMCD3 cell lines: one expressing wild-type UT-A1 and one expressing a mutated form of UT-A1, S486A/S499A, that is unresponsive to protein kinase A. Forskolin stimulates urea flux in the wild-type UT-A1-mIMCD3 cells but not in the S486A/S499A-UT-A1-mIMCD3 cells. The phospho-S486-UT-A1 antibody identified UT-A1 protein in the wild-type UT-A1-mIMCD3 cells but not in the S486A/S499A-UT-A1-mIMCD3 cells. In rat IMCDs, forskolin increased the abundance of phospho-S486-UT-A1 (measured using the phospho-S486 antibody) and of total UT-A1 phosphorylation (measured by 32P incorporation). Forskolin also increased the plasma membrane accumulation of phospho-S486-UT-A1 in rat IMCD suspensions, as measured by biotinylation. In rats treated with vasopressin in vivo, the majority of the phospho-S486-UT-A1 appears in the apical plasma membrane. In summary, we developed stably transfected mIMCD3 cell lines expressing UT-A1 and an S486-UT-A1 phospho-specific antibody. We confirmed that vasopressin increases UT-A1 accumulation in the apical plasma membrane and showed that vasopressin phosphorylates UT-A1 at S486 in rat IMCDs and that the S486-phospho-UT-A1 form is primarily detected in the apical plasma membrane.

scholarly journals Crp-Like Protein Plays Both Positive and Negative Roles in Regulating the Pathogenicity of Bacterial Pustule Pathogen Xanthomonas axonopodis pv. glycines

2019 ◽  
Vol 109 (7) ◽  
pp. 1171-1183 ◽  
Author(s):  
Wei Guo ◽  
Jie Gao ◽  
Qingshan Chen ◽  
Bojun Ma ◽  
Yuan Fang ◽  
...  
Keyword(s):  
Cell Motility ◽  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Extracellular Polysaccharide ◽  
Polymerase Chain Reaction Analysis ◽  
Single Copy ◽  
Wild Type ◽  
Cell Wall Degrading Enzymes ◽  
In The Wild

The global regulator Crp-like protein (Clp) is positively involved in the production of virulence factors in some of the Xanthomonas spp. However, the functional importance of Clp in X. axonopodis pv. glycines has not been investigated previously. Here, we showed that deletion of clp led to significant reduction in the virulence of X. axonopodis pv. glycines in soybean, which was highly correlated with the drastic reductions in carbohydrates utilization, extracellular polysaccharide (EPS) production, biofilm formation, cell motility, and synthesis of cell wall degrading enzymes (CWDEs). These significantly impaired properties in the clp mutant were completely rescued by a single-copy integration of the wild-type clp into the mutant chromosome via homologous recombination. Interestingly, overexpression of clp in the wild-type strain resulted in significant increases in cell motility and synthesis of the CWDEs. To our surprise, significant reductions in carbohydrates utilization, EPS production, biofilm formation, and the protease activity were observed in the wild-type strain overexpressing clp, suggesting that Clp also plays a negative role in these properties. Furthermore, quantitative reverse transcription polymerase chain reaction analysis suggested that clp was positively regulated by the diffusible signal factor-mediated quorum-sensing system and the HrpG/HrpX cascade. Taken together, our results reveal that Clp functions as both activator and repressor in multiple biological processes in X. axonopodis pv. glycines that are essential for its full virulence.

scholarly journals Role of cationic amino acids in the Na+/dicarboxylate co-transporter NaDC-1

2000 ◽  
Vol 350 (3) ◽  
pp. 677-683 ◽  
Author(s):  
Ana M. PAJOR ◽  
Esther S. KAHN ◽  
Rama GANGULA
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Xenopus Oocytes ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Wild Type ◽  
Conserved Residues ◽  
In The Wild ◽  
Cationic Amino Acids

The role of cationic amino acids in the Na+/dicarboxylate co-transporter NaDC-1 was investigated by site-directed mutagenesis and subsequent expression of mutant transporters in Xenopus oocytes. Of the ten residues chosen for mutagenesis, eight (Lys-34, Lys-107, Arg-108, Lys-333, Lys-390, Arg-368, Lys-414 and Arg-541) were found to be non-essential for function or targeting. Only two conserved residues, Lys-84 (at the cytoplasmic end of helix 3) and Arg-349 (at the extracellular end of helix 7), were found to be important for transport. Both mutant transporters were expressed at the plasma membrane. The mutation of Lys-84 to Ala resulted in an increased Km for succinate of 1.8mM, compared with 0.3mM in the wild-type NaDC-1. The R349A mutant had Na+ and citrate kinetics that were similar to those of the wild type. However, succinate handling in the R349A mutant was altered, with evidence of inhibition at high succinate concentrations. In conclusion, charge neutralization of Lys-84 and Arg-349 in NaDC-1 affects succinate handling, suggesting that these residues might have roles in substrate binding.

scholarly journals Establishment and characterization of Neu1-knockout zebrafish and its abnormal clinical phenotypes

2020 ◽  
Author(s):  
Keiji Okada ◽  
Ryo Takase ◽  
Yurie Hamaoka ◽  
Akinobu Honda ◽  
Asami Ikeda ◽  
...  
Keyword(s):  
Animal Model ◽  
Plasma Membrane ◽  
Sialic Acid ◽  
Danio Rerio ◽  
Cancer Metastasis ◽  
Expression Patterns ◽  
Wild Type ◽  
Fish Embryo ◽  
Neu1 Sialidase

Mammalian sialidase Neu1 is involved in various physiological functions, including cell adhesion, differentiation, cancer metastasis, and diabetes through lysosomal catabolism and desialylation of glycoproteins at the plasma membrane. Various animal models have been established to further explore the functions of vertebrate Neu1. The present study focused on zebrafish (Danio rerio) belonging to Cypriniformes as an experimental animal model with neu1 gene deficiency. The results revealed that the zebrafish Neu1 desialyzed both a2-3 and a2-6 sialic acid linkages from oligosaccharides and glycoproteins at pH 4.5, and it is highly conserved with other fish species and mammalian Neu1. Further, Neu1-knockout zebrafish (Neu1-KO) was established through CRISPR/Cas9 genome editing. Neu1-KO fish exhibited slight abnormal embryogenesis with the accumulation of pleural effusion; however, no embryonic lethality was observed. Although Neu1-KO fish were able to be maintained as homozygous, they showed smaller body length and weight than the wild type (WT) fish, and muscle atrophy and curvature of the vertebra were observed in adult Neu1-KO fish (8 months). The expression patterns of myod and myog transcription factors regulating muscle differentiation varied between Neu1-KO and WT fish embryo. Expression of lysosomal-related genes, including ctsa,lamp1a, and tfeb were upregulated in adult Neu1-KO muscle as compared to WT. Furthermore, the expression pattern of genes involved in bone remodeling (runx2a, runx2b, and mmp9) was decreased in Neu1-KO fish. These phenotypes were quite similar to those of Neu1-KO mice and human sialidosis patients, indicating the effectiveness of the established Neu1-KO zebrafish for the study of vertebrate Neu1 sialidase.

scholarly journals Wild-Type p53 Attenuates Cancer Cell Motility by Inducing Growth Differentiation Factor-15 Expression

Endocrinology ◽  
2011 ◽  
Vol 152 (8) ◽  
pp. 2987-2995 ◽  
Author(s):  
Jung-Chien Cheng ◽  
Hsun-Ming Chang ◽  
Peter C. K. Leung
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Cancer Cell ◽  
Cell Movement ◽  
Migration And Invasion ◽  
Wild Type ◽  
Growth Differentiation Factor 15 ◽  
Cancer Cell Motility ◽  
Differentiation Factor ◽  
Wild Type P53

A major function of the p53 tumor suppressor is the regulation of the cell cycle and apoptosis. In addition to its well-documented functions in malignant cancer cells, p53 can also regulate cell migration and invasion, which contribute to metastasis. Growth differentiation factor-15 (GDF-15), a member of the TGF-β superfamily, has been shown to be a downstream target of p53 and is associated with diverse human diseases and cancer progression. In this study, we examined the potential role of GDF-15 in p53-regulated cancer cell motility. We show that overexpression of wild-type p53 in two highly invasive p53-null human cancer cell lines, SKOV3 and PC3, attenuated cell migration and the movement through Matrigel. Using wild-type p53 and DNA-binding-deficient p53 mutants, we found that the transcriptional activity of p53 is required in the induction of GDF-15 expression. Cell movement through uncoated and Matrigel-coated transwell decreased in response to treatment with recombinant GDF-15, whereas the cell proliferation was not affected by GDF-15 treatment. Moreover, the induction of GDF-15 expression and secretion by p53 and the reduction in cell movement through Matrigel were diminished by treatment with GDF-15 small interfering RNA. This study demonstrates a mechanism by which p53 attenuates cancer cell motility through GDF-15 expression. In addition, our results indicate that GDF-15 mediates the functions of p53 by autocrine/paracrine action.

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