scholarly journals Mechanotransduction in an extracted cell model: Fyn drives stretch- and flow-elicited PECAM-1 phosphorylation

2008 ◽  
Vol 182 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Yi-Jen Chiu ◽  
Elena McBeath ◽  
Keigi Fujiwara
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Adhesion Molecule ◽  
Mammalian Cells ◽  
Kinase Inhibitors ◽  
Vascular Endothelial Cells ◽  
Cell Model ◽  
Vascular Endothelial ◽  
Small Interfering Rnas ◽  
Essential Components

Mechanosensing followed by mechanoresponses by cells is well established, but the mechanisms by which mechanical force is converted into biochemical events are poorly understood. Vascular endothelial cells (ECs) exhibit flow- and stretch-dependent responses and are widely used as a model for studying mechanotransduction in mammalian cells. Platelet EC adhesion molecule 1 (PECAM-1) is tyrosine phosphorylated when ECs are exposed to flow or when PECAM-1 is directly pulled, suggesting that it is a mechanochemical converter. We show that PECAM-1 phosphorylation occurs when detergent-extracted EC monolayers are stretched, indicating that this phosphorylation is mechanically triggered and does not require the intact plasma membrane and soluble cytoplasmic components. Using kinase inhibitors and small interfering RNAs, we identify Fyn as the PECAM-1 kinase associated with the model. We further show that stretch- and flow-induced PECAM-1 phosphorylation in intact ECs is abolished when Fyn expression is down-regulated. We suggest that PECAM-1 and Fyn are essential components of a PECAM-1–based mechanosensory complex in ECs.

scholarly journals Identification of Fer Tyrosine Kinase Localized on Microtubules as a Platelet Endothelial Cell Adhesion Molecule-1 Phosphorylating Kinase in Vascular Endothelial Cells

2003 ◽  
Vol 14 (9) ◽  
pp. 3553-3564 ◽  
Author(s):  
Naoko Kogata ◽  
Michitaka Masuda ◽  
Yuji Kamioka ◽  
Akiko Yamagishi ◽  
Akira Endo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Adhesion Molecule ◽  
Intracellular Signaling ◽  
Vascular Endothelial Cells ◽  
Expression Cloning ◽  
Vascular Endothelial ◽  
Cell Contacts ◽  
Cell Cell

Platelet endothelial adhesion molecule-1 (PECAM-1) is a part of intercellular junctions and triggers intracellular signaling cascades upon homophilic binding. The intracellular domain of PECAM-1 is tyrosine phosphorylated upon homophilic engagement. However, it remains unclear which tyrosine kinase phosphorylates PECAM-1. We sought to isolate tyrosine kinases responsible for PECAM-1 phosphorylation and identified Fer as a candidate, based on expression cloning. Fer kinase specifically phosphorylated PECAM-1 at the immunoreceptor tyrosine-based inhibitory motif. Notably, Fer induced tyrosine phosphorylation of SHP-2, which is known to bind to the immunoreceptor tyrosine-based inhibitory motif of PECAM-1, and Fer also induced tyrosine phosphorylation of Gab1 (Grb2-associated binder-1). Engagement-dependent PECAM-1 phosphorylation was inhibited by the overexpression of a kinase-inactive mutant of Fer, suggesting that Fer is responsible for the tyrosine phosphorylation upon PECAM-1 engagement. Furthermore, by using green fluorescent protein-tagged Fer and a time-lapse fluorescent microscope, we found that Fer localized at microtubules in polarized and motile vascular endothelial cells. Fer was dynamically associated with growing microtubules in the direction of cell-cell contacts, where p120catenin, which is known to associate with Fer, colocalized with PECAM-1. These results suggest that Fer localized on microtubules may play an important role in phosphorylation of PECAM-1, possibly through its association with p120catenin at nascent cell-cell contacts.

A mathematical model of plasma membrane electrophysiology and calcium dynamics in vascular endothelial cells

2007 ◽  
Vol 293 (1) ◽  
pp. C277-C293 ◽  
Author(s):  
Haroldo S. Silva ◽  
Adam Kapela ◽  
Nikolaos M. Tsoukias
Keyword(s):  
Mathematical Model ◽  
Endothelial Cells ◽  
Plasma Membrane ◽  
Vascular Tone ◽  
Vascular Endothelial Cells ◽  
Anion Channel ◽  
Ionic Species ◽  
Vascular Endothelial ◽  
Health And Disease ◽  
Vascular Autoregulation

Vascular endothelial cells (ECs) modulate smooth muscle cell (SMC) contractility, assisting in vascular tone regulation. Cytosolic Ca2+ concentration ([Ca2+]i) and membrane potential ( Vm) play important roles in this process by controlling EC-dependent vasoactive signals and intercellular communication. The present mathematical model integrates plasmalemma electrophysiology and Ca2+ dynamics to investigate EC responses to different stimuli and the controversial relationship between [Ca2+]i and Vm. The model contains descriptions for the intracellular balance of major ionic species and the release of Ca2+ from intracellular stores. It also expands previous formulations by including more detailed transmembrane current descriptions. The model reproduces Vm responses to volume-regulated anion channel (VRAC) blockers and extracellular K+ concentration ([K+]o) challenges, predicting 1) that Vm changes upon VRAC blockade are [K+]o dependent and 2) a biphasic response of Vm to increasing [K+]o. Simulations of agonist-induced Ca2+ mobilization replicate experiments under control and Vm hyperpolarization blockade conditions. They show that peak [Ca2+]i is governed by store Ca2+ release while Ca2+ influx (and consequently Vm) impacts more the resting and plateau [Ca2+]i. The Vm sensitivity of rest and plateau [Ca2+]i is dictated by a [Ca2+]i “buffering” system capable of masking the Vm-dependent transmembrane Ca2+ influx. The model predicts plasma membrane Ca2+-ATPase and Ca2+ permeability as main players in this process. The heterogeneous Vm impact on [Ca2+]i may elucidate conflicting reports on how Vm influences EC Ca2+. The present study forms the basis for the development of multicellular EC-SMC models that can assist in understanding vascular autoregulation in health and disease.

scholarly journals Ectoadenylate Kinase and Plasma Membrane ATP Synthase Activities of Human Vascular Endothelial Cells

2006 ◽  
Vol 281 (30) ◽  
pp. 20728-20737 ◽  
Author(s):  
Ellen E. Quillen ◽  
Gale C. Haslam ◽  
Hardeep S. Samra ◽  
Darius Amani-Taleshi ◽  
Jeffrey A. Knight ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Atp Synthase ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial
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