Endoglin regulates cytoskeletal organization through binding to ZRP-1, a member of the Lim family of proteins.
Endoglin is a component of the transforming growth factor-beta receptor complex abundantly expressed at the surface of endothelial cells and plays an important role in cardiovascular development and vascular remodeling. By using the cytoplasmic domain of endoglin as a bait for screening protein interactors, we have identified ZRP-1 (zyxin-related protein 1), a 476-amino acid member that belongs to a family of LIM containing proteins that includes zyxin and lipoma-preferred partner. The endoglin interacting region was mapped within the three double zinc finger LIM domains of the ZRP-1 C terminus. Analysis of the subcellular distribution of ZRP-1 demonstrated that in the absence of endoglin, ZRP-1 mainly localizes to focal adhesion sites, whereas in the presence of endoglin ZRP-1 is found along actin stress fibers. Because the LIM family of proteins has been shown to associate with the actin cytoskeleton, we investigated the possibility of a regulatory role for endoglin with regard to this structure. Expression of endoglin resulted in a dramatic reorganization of the actin cytoskeleton. In the absence of endoglin, F-actin was localized to dense aggregates of bundles, whereas in the presence of endoglin, expressed in endothelial cells, F-actin was in stress fibers and colocalized with ZRP-1. Furthermore, small interfering RNA-mediated suppression of endoglin or ZRP-1, or clustering of endoglin in endothelial cells, led to mislocalization of F-actin fibers. These results suggest a regulatory role for endoglin, via its interaction with ZRP-1, in the actin cytoskeletal organization.
Sanz-Rodriguez
Francisco
F
Centro de Investigaciones Biológicas, CSIC, Ramiro de Maetzu 9, 28040 Madrid, Spain. francisco.sanz@uam.es
Guerrero-Esteo
Mercedes
M
Botella
Luisa-Maria
LM
Banville
Denis
D
Vary
Calvin P H
CP
Bernabéu
Carmelo
C
D000074183:ATPases Associated with Diverse Cellular Activities; D000199:Actins / Q000737:chemistry; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015703:Antigens, CD; D015153:Blotting, Western; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D000071063:Endoglin; D004730:Endothelium, Vascular / Q000166:cytology; D006801:Humans; D060588:LIM Domain Proteins; D008856:Microscopy, Fluorescence; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011956:Receptors, Cell Surface; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism*
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D002352:Carrier Proteins; D018076:DNA, Complementary; C064206:ENG protein, human; D000071063:Endoglin; D060588:LIM Domain Proteins; C092282:PSMC5 protein, human; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D019010:Vascular Cell Adhesion Molecule-1; D046988:Proteasome Endopeptidase Complex; D000074183:ATPases Associated with Diverse Cellular Activities