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Podoplanin silencing disrupts membrane localization of phosphorylated ezrin/radixin/moesin proteins (ERM) and impairs capillary tube formation in lymphatic endothelial cells
Author(s) -
Olmo Maria A Navarro,
Xu Dong,
Rezaiekhaligh Mo,
Mabry Sherry,
Perez Ricardo E,
Truog William E,
Ekekezie Ikechukwu I
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1201-a
Subject(s) - podoplanin , transfection , lymphatic endothelium , moesin , microbiology and biotechnology , ezrin , lymphatic system , endothelium , chemistry , phosphorylation , endothelial stem cell , biology , cell , cell culture , cytoskeleton , immunology , biochemistry , in vitro , genetics , endocrinology
Podoplanin (also known as gp36, T1 alpha protein, Oct 8, E11 and PA2.2) is a type I membrane glycoprotein expressed in cells of different origin whose biological function remains largely unknown. It is present in lymphatic endothelia, and absent in endothelial cells from blood vessels. Our objective was to investigate the potential role of podoplanin in the process of capillary tube formation in lymphatic endothelial cells. Methods: Human lung microvascular lymphatic endothelial cells (HMVEC‐LLy) were transfected with control siRNA or siRNA for podoplanin and 48 hours later cells were plated on Matrigel TM to induce capillary tube formation. Formation of tubes was analyzed at specific times, and immunocytochemistry for ERM family of actin‐binding proteins and their phosphorylated form was performed. Results: Cells transfected with podoplanin siRNA failed to form capillary tubes in Matrigel TM , unlike controls transfected with scramble siRNA. Immunocytochemical analysis showed that phosphorylated ERM proteins failed to localize to cell membrane focal adhesion complexes in podoplanin siRNA transfected cells as compared to findings in controls. Conclusions: Podoplanin has a critical role in capillary tube formation by HMVEC‐LLy when cultured in Matrigel TM . Failure of phosphorylated ERM proteins to localize to cell membrane focal adhesion complexes in the absence of podoplanin points to a possible mechanism.