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Osteoblast Adhesion Dynamics: A Possible Role for ROS and LMW‐PTP
Author(s) -
Fernandes Gustavo V. O.,
Cavagis Alexandre D. M.,
Ferreira Carmen V.,
Olej Beni,
de Souza Leão Maurício,
Yano Cláudia L.,
Peppelenbosch Maikel,
Granjeiro José Mauro,
Zambuzzi Willian F.
Publication year - 2014
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.24691
Subject(s) - phosphorylation , microbiology and biotechnology , tyrosine phosphorylation , chemistry , protein tyrosine phosphatase , focal adhesion , reactive oxygen species , osteoblast , cell adhesion , intracellular , proto oncogene tyrosine protein kinase src , biochemistry , biology , in vitro , cell
Reactive oxygen species (ROS) modulate a variety of intracellular events, but their role in osteoblast adhesion and spreading remains unclear. ROS is a very‐known physiological modulators of Protein Tyrosine Phosphatases activities, mainly to low molecular weight protein tyrosine phosphatase (LMW‐PTP) activity. As this biological mechanism is not clear in osteoblast adhesion, we decided to investigate ROS levels and phosphorylations of FAK and Src, identifying these proteins as potential substrates to LMW‐PTP activity. Our results showed that during osteoblast adhesion/spreading (30 min and 2 h of seeding) the intracellular ROS content (hydrogen peroxide) is finely regulated by an effective anti‐oxidant system [catalase and Superoxide Dismutase (SOD) activities were evaluated]. During the first 30 min of adhesion, there was an increase in ROS production and a concomitant increase in focal adhesion kinase (FAK) activity after its phosphorylation at Tyrosine 397 (Y 397 ). Moreover, after 2 h there was a decrease in ROS content and FAK phosphorylation. There was no significant change in LMW‐PTP expression at 30 min or 2 h. In order to validate our hypothesis that LMW‐PTP is able to control FAK activity by modulating its phosphorylation status, we decided to overexpress and silence LMW‐PTP in this context. Our results showed that FAK phosphorylation at Y 397 was increased and decreased in osteoblasts with silenced or overexpressed LMW‐PTP, respectively. Together, these data show that ROS modulate FAK phosphorylation by an indirect way, suggesting that a LMW‐PTP/FAK supra‐molecular complex is involved in transient responses during osteoblast adhesion and spreading. J. Cell. Biochem. 115: 1063–1069, 2014. © 2013 Wiley Periodicals, Inc.