Receptor dynamics regulates actin polymerization state through phosphorylation of cofilin in mast cells

2021 ◽  
Vol 534 ◽  
pp. 714-719
Author(s):  
Ruriko Suzuki ◽  
Yoshikazu Inoh ◽  
Satoru Yokawa ◽  
Tadahide Furuno ◽  
Naohide Hirashima
2005 ◽  
Vol 201 (6) ◽  
pp. 859-870 ◽  
Author(s):  
Junko Sasaki ◽  
Takehiko Sasaki ◽  
Masakazu Yamazaki ◽  
Kunie Matsuoka ◽  
Choji Taya ◽  
...  

The membrane phospholipid phosphatidylinositol 4, 5-bisphosphate [PI(4,5)P2] is a critical signal transducer in eukaryotic cells. However, the physiological roles of the type I phosphatidylinositol phosphate kinases (PIPKIs) that synthesize PI(4,5)P2 are largely unknown. Here, we show that the α isozyme of PIPKI (PIPKIα) negatively regulates mast cell functions and anaphylactic responses. In vitro, PIPKIα-deficient mast cells exhibited increased degranulation and cytokine production after Fcε receptor-I cross-linking. In vivo, PIPKIα−/− mice displayed enhanced passive cutaneous and systemic anaphylaxis. Filamentous actin was diminished in PIPKIα−/− mast cells, and enhanced degranulation observed in the absence of PIPKIα was also seen in wild-type mast cells treated with latrunculin, a pharmacological inhibitor of actin polymerization. Moreover, the association of FcεRI with lipid rafts and FcεRI-mediated activation of signaling proteins was augmented in PIPKIα−/− mast cells. Thus, PIPKIα is a negative regulator of FcεRI-mediated cellular responses and anaphylaxis, which functions by controlling the actin cytoskeleton and dynamics of FcεRI signaling. Our results indicate that the different PIPKI isoforms might be functionally specialized.


1994 ◽  
Vol 126 (4) ◽  
pp. 1005-1015 ◽  
Author(s):  
J C Norman ◽  
L S Price ◽  
A J Ridley ◽  
A Hall ◽  
A Koffer

Rat peritoneal mast cells, both intact and permeabilized, have been used widely as model secretory cells. GTP-binding proteins and calcium play a major role in controlling their secretory response. Here we have examined changes in the organization of actin filaments in intact mast cells after activation by compound 48/80, and in permeabilized cells after direct activation of GTP-binding proteins by GTP-gamma-S. In both cases, a centripetal redistribution of cellular F-actin was observed: the content of F-actin was reduced in the cortical region and increased in the cell interior. The overall F-actin content was increased. Using permeabilized cells, we show that AIF4-, an activator of heterotrimeric G proteins, induces the disassembly of F-actin at the cortex, while the appearance of actin filaments in the interior of the cell is dependent on two small GTPases, rho and rac. Rho was found to be responsible for de novo actin polymerization, presumably from a membrane-bound monomeric pool, while rac was required for an entrapment of the released cortical filaments. Thus, a heterotrimeric G-protein and the small GTPases, rho and rac, participate in affecting the changes in the actin cytoskeleton observed after activation of mast cells.


1997 ◽  
Vol 62 (4) ◽  
pp. 535-546 ◽  
Author(s):  
Anne L. Hall ◽  
Bridget S. Wilson ◽  
Janet R. Pfeiffer ◽  
Janet M. Oliver ◽  
Larry A. Sklar

2020 ◽  
Author(s):  
Bing Sun ◽  
Xin Jiang ◽  
Rongmei Qu ◽  
Tingyu Fan ◽  
Yuchao Yang ◽  
...  

Abstract Background:Actin is an essential cellular protein that assembles into microfilaments and regulates numerous processes such as cell migration, maintenance of cell shape, and material transport. In this study, we explored the effect of actin polymerization state on the osteogenic differentiation of human adipose-derived stem cells (hASCs). Methods:The hASCs were treated with different concentrations (0, 1, 5, 10, 20, and 50 nM)of jasplakinolide (JAS), a reagent that directly polymerizes F-actin.The effects ofthe actin polymerization state on cell proliferation, apoptosis, migration, and the maturity of focal adhesion-related proteins were assessed. In addition, western blotting and alizarin red staining assays were performed to assess osteogenic differentiation. Results: These results revealed that cell proliferation and migration in the JAS (0, 1, 5, 10, and 20 nM) groupswashigher than that inthe control group andthe JAS (50 nM) group.The protein expressionof focal adhesion kinase, vinculin, paxillin, and talinwere highest in the JAS (20 nM) group, whilezyxin expression was highestinthe JAS (50 nM) group.Western blottingshowed thatosteogenic differentiation in theJAS (0, 1, 5, 10, 20, and 50 nM) groupswas enhanced compared with that in thecontrol group, and was strongest inthe JAS (50 nM) group.Conclusions: Our data suggest thatthe actinpolymerization state may promote the osteogenic differentiation of hASCs by regulating the protein expression of focal adhesion-associated proteins in a concentration-dependent manner. Our findings provide valuable information for exploring the mechanism of osteogenic differentiationin hASCs.


2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Bing Sun ◽  
Rongmei Qu ◽  
Tingyu Fan ◽  
Yuchao Yang ◽  
Xin Jiang ◽  
...  

Abstract Background Actin is an essential cellular protein that assembles into microfilaments and regulates numerous processes such as cell migration, maintenance of cell shape, and material transport. Methods In this study, we explored the effect of actin polymerization state on the osteogenic differentiation of human adipose-derived stem cells (hASCs). The hASCs were treated for 7 days with different concentrations (0, 1, 5, 10, 20, and 50 nM) of jasplakinolide (JAS), a reagent that directly polymerizes F-actin. The effects of the actin polymerization state on cell proliferation, apoptosis, migration, and the maturity of focal adhesion-related proteins were assessed. In addition, western blotting and alizarin red staining assays were performed to assess osteogenic differentiation. Results Cell proliferation and migration in the JAS (0, 1, 5, 10, and 20 nM) groups were higher than in the control group and the JAS (50 nM) group. The FAK, vinculin, paxillin, and talin protein expression levels were highest in the JAS (20 nM) group, while zyxin expression was highest in the JAS (50 nM) group. Western blotting showed that osteogenic differentiation in the JAS (0, 1, 5, 10, 20, and 50 nM) group was enhanced compared with that in the control group, and was strongest in the JAS (50 nM) group. Conclusions In summary, our data suggest that the actin polymerization state may promote the osteogenic differentiation of hASCs by regulating the protein expression of focal adhesion-associated proteins in a concentration-dependent manner. Our findings provide valuable information for exploring the mechanism of osteogenic differentiation in hASCs.


Blood ◽  
2007 ◽  
Vol 109 (9) ◽  
pp. 3679-3686 ◽  
Author(s):  
Lionel A. Samayawardhena ◽  
Reuben Kapur ◽  
Andrew W. B. Craig

Abstract Kit receptor and its ligand stem cell factor (SCF) are critical regulators of mast cell production, proliferation, degranulation, and chemotaxis. In this study, we investigated how Fyn kinase regulates chemotaxis of mast cells toward SCF. On β1-integrin engagement, Fyn-deficient (fyn−/−) mast cells displayed a striking defect in cell spreading and lamellipodia formation compared to wild-type mast cells. The hematopoietic-specific Src family kinases (Lyn/Fgr/Hck) were not required for initial SCF-induced cell spreading. Reduced SCF-induced activation of Rac1 and Rac2 GTPases, p38 mitogen-activated protein kinase, and filamentous actin polymerization was observed in fyn−/− mast cells compared to wild-type mast cells. Retroviral-mediated expression of Fyn, constitutively active forms of Rac2 or phosphatidylinositol 3-kinase (PI3K) in fyn−/− mast cells rescued defects in SCF-induced cell polarization and chemotaxis of Fyn-deficient mast cells. Thus, we conclude that Fyn kinase plays a unique role upstream of PI3K and Rac GTPases to promote the reorganization of the cytoskeleton during mast cell spreading and chemotaxis.


2019 ◽  
Author(s):  
Nirmalya Bag ◽  
David A. Holowka ◽  
Barbara A. Baird

ABSTRACTA myriad of transient, nanoscopic lipid- and protein-based interactions confer a steady-state organization of plasma membrane in resting cells that is poised to orchestrate assembly of key signaling components upon reception of an extracellular stimulus. Although difficult to observe directly in live cells, these subtle interactions can be discerned by their impact on the diffusion of membrane constituents. Herein, we quantified the diffusion properties of a panel of structurally distinct lipid-anchored and transmembrane (TM) probes in RBL mast cells by multiplexed Imaging Fluorescence Correlation Spectroscopy. We developed a statistical analysis of data combined from many pixels over multiple cells to characterize differences as small as 10% in diffusion coefficients, which reflect differences in underlying interactions. We found that the distinctive diffusion properties of lipid-anchored probes can be explained by their dynamic partitioning into ordered proteo-lipid nanodomains, which encompass a major fraction of the membrane and whose physical properties are influenced by actin polymerization. Effects on diffusion by functional protein modules in both lipid-anchored and TM probes reflect additional complexity in steady-state membrane organization. The contrast we observe between different probes diffusing through the same membrane milieu represent the dynamic resting steady-state, which serves as a baseline for monitoring plasma membrane remodeling that occurs upon stimulation.


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