scholarly journals Two isotypes of phosphatidylinositol 3‐phosphate ‐ binding sorting nexins play distinct roles in trogocytosis in Entamoeba histolytica

2019 ◽  
Vol 22 (3) ◽  
Author(s):  
Natsuki Watanabe ◽  
Kumiko Nakada‐Tsukui ◽  
Tomoyoshi Nozaki
Keyword(s):  
Entamoeba Histolytica ◽  
Phosphate Binding ◽  
Sorting Nexins ◽  
Phosphatidylinositol 3

scholarly journals Characterization of PXK as a Protein Involved in Epidermal Growth Factor Receptor Trafficking

2010 ◽  
Vol 30 (7) ◽  
pp. 1689-1702 ◽  
Author(s):  
Hiroshi Takeuchi ◽  
Takako Takeuchi ◽  
Jing Gao ◽  
Lewis C. Cantley ◽  
Masato Hirata
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Receptor Trafficking ◽  
Phosphate Binding ◽  
Sorting Nexins ◽  
Px Domain ◽  
Epidermal Growth ◽  
Phosphatidylinositol 3

ABSTRACT The phox homology (PX) domain is a phosphoinositide-binding module that typically binds phosphatidylinositol 3-phosphate. Out of 47 mammalian proteins containing PX domains, more than 30 are denoted sorting nexins and several of these have been implicated in internalization of cell surface proteins to the endosome, where phosphatidylinositol-3-phosphate is concentrated. Here we investigated a multimodular protein termed PXK, composed of a PX domain, a protein kinase-like domain, and a WASP homology 2 domain. We show that the PX domain of PXK localizes this protein to the endosomal membrane via binding to phosphatidylinositol 3-phosphate. PXK expression in COS7 cells accelerated the ligand-induced internalization and degradation of epidermal growth factor receptors by a mechanism requiring phosphatidylinositol 3-phosphate binding but not involving the WASP homology 2 domain. Conversely, depletion of PXK using RNA interference decreased the rate of epidermal growth factor receptor internalization and degradation. Ubiquitination of epidermal growth factor receptor by the ligand stimulation was enhanced in PXK-expressing cells. These results indicate that PXK plays a critical role in epidermal growth factor receptor trafficking through modulating ligand-induced ubiquitination of the receptor.

scholarly journals Characterization of VPS34-IN1, a selective inhibitor of Vps34, reveals that the phosphatidylinositol 3-phosphate-binding SGK3 protein kinase is a downstream target of class III phosphoinositide 3-kinase

2014 ◽  
Vol 463 (3) ◽  
pp. 413-427 ◽  
Author(s):  
Ruzica Bago ◽  
Nazma Malik ◽  
Michael J. Munson ◽  
Alan R. Prescott ◽  
Paul Davies ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Selective Inhibitor ◽  
Class Iii ◽  
Phosphate Binding ◽  
Downstream Target ◽  
Phosphoinositide 3 Kinase ◽  
Phosphatidylinositol 3

We characterize VPS34-IN, a potent and selective inhibitor of class III Vps34 PI3K. Using VPS34-IN1, we demonstrate that PtdIns(3)P, produced by Vps34 controls phosphorylation and activity of the SGK3 protein kinase.

scholarly journals Enhanced resistance inTheobroma cacaoagainst oomycete and fungal pathogens by secretion of phosphatidylinositol-3-phosphate-binding proteins

2015 ◽  
Vol 14 (3) ◽  
pp. 875-886 ◽  
Author(s):  
Emily E. Helliwell ◽  
Julio Vega-Arreguín ◽  
Zi Shi ◽  
Bryan Bailey ◽  
Shunyuan Xiao ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Binding Proteins ◽  
Phosphate Binding ◽  
Enhanced Resistance ◽  
Phosphatidylinositol 3

scholarly journals Induction of Monocyte Chemotactic Protein 1 in Colonic Epithelial Cells by Entamoeba histolytica Is Mediated via the Phosphatidylinositol 3-Kinase/p65 Pathway

2007 ◽  
Vol 75 (4) ◽  
pp. 1765-1770 ◽  
Author(s):  
Srinivas J. Kammanadiminti ◽  
Indranil Dey ◽  
Kris Chadee
Keyword(s):  
Epithelial Cells ◽  
Entamoeba Histolytica ◽  
Pi3 Kinase ◽  
Classical Pathway ◽  
Phosphatidylinositol 3 Kinase ◽  
Colonic Epithelial Cells ◽  
Monocyte Chemotactic Protein ◽  
Mrna Induction ◽  
Chemotactic Protein ◽  
Phosphatidylinositol 3

ABSTRACT The role intestinal epithelial cells play in the pathogenesis of amebic colitis is poorly understood. Herein, we demonstrate that secreted and soluble ameba (Entamoeba histolytica) proteins (SAP) induce expression of the chemoattractant monocyte chemotactic protein (MCP) in the colonic epithelial cell lines Caco-2, T84, and LS174T. MCP-1 mRNA induction was both dose and time dependent, with peak induction occurring at 8 h and with 100 μg/ml of SAP. Significant increase in MCP-1 protein expression was observed after 12 h. SAP failed to activate any of the mitogen-activated protein kinase pathways or IκB kinase activity. Moreover, inhibiting the classical pathway of NF-κB activation did not affect SAP-induced MCP-1 expression. Instead, we find that SAP-induced MCP-1 expression is dependent on posttranslational modification of the NFκB p65 subunit. SAP induced phosphorylation of p65 and enhanced NF-κB transcriptional activity, which are phosphatidylinositol 3-kinase (PI3 kinase) dependent. Treatment with PI3 kinase inhibitor LY290004 significantly abrogated the activation of Akt, p65, and MCP-1 mRNA induction. We conclude that colonic epithelial cells play a role in the initiation of inflammation by secreting chemokines in response to soluble ameba components.

Entamoeba histolytica: FYVE-finger domains, phosphatidylinositol 3-phosphate biosensors, associate with phagosomes but not fluid filled endosomes

2006 ◽  
Vol 112 (4) ◽  
pp. 221-231 ◽  
Author(s):  
R.R. Powell ◽  
B.H. Welter ◽  
R. Hwu ◽  
B. Bowersox ◽  
C. Attaway ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Phosphatidylinositol 3

Regulation of early-endosome dynamics by phosphatidylinositol 3-phosphate binding proteins

1999 ◽  
Vol 27 (4) ◽  
pp. 662-666 ◽  
Author(s):  
M. J. Clague ◽  
A. T. Jones ◽  
I. G. Mills ◽  
D. M. Walker ◽  
S. Urbé
Keyword(s):  
Binding Proteins ◽  
Early Endosome ◽  
Phosphate Binding ◽  
Phosphatidylinositol 3
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