Subcellular distribution of Wnt-1 at adherens junctions and actin-rich densities in endothelial cells

• Published in: Experimental cell research Vol. 288; no. 2; pp. 335 - 343
• Main Authors: Wechezak, Arlene R, Coan, Daniel E
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-08-2003
• Subjects: Actin-rich-densities; Actins - metabolism; Adherens junctions; Adherens Junctions - metabolism; Animals; beta Catenin; Cattle; Cell Fractionation; Cells, Cultured; Cytoskeletal Proteins - metabolism; Endothelial cells; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Mice; Microscopy, Video; Mitogens - metabolism; Oligonucleotides, Antisense; Proto-Oncogene Proteins - chemistry; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Trans-Activators - metabolism; Wnt Proteins; Wnt-1; Wnt1 Protein; Zebrafish Proteins; β-catenin; β-catenin; Adherens junctions; Actin-rich-densities; Wnt-1; Endothelial cells
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1016/S0014-4827(03)00232-5

The
Wnt family of signaling proteins functions in embryonic development and mammalian oncogenesis. It is unknown whether these molecules have a role in normal, postdevelopmental, homeostatic processes. Possessing a putative signal sequence and potential glycosylation sites,
Wnt-1 is believed to be secreted and remain associated with the cell surface and extracellular matrix. While it has been suggested that
Wnt proteins may target cytoskeletal structures more directly, no definitive studies have identified an intracellular association and function for these molecules. Here, we report that Western blots of lysates from retinoic-acid-differentiated P19 cells and bovine endothelial cells indicate the presence of a 45-kDa
Wnt-1 protein. In endothelium,
Wnt-1 was present in both the Triton X soluble and the insoluble cell fractions. Immunocytochemical labeling localized
Wnt-1 to adherens junctions, codistributing with β-catenin.
Wnt-1 also was detected at actin-rich densities (ARDs) within basal cell regions. In wounded monolayers, ARDs delineated the distal margins of cells undergoing directed migration. Transfection with antisense oligonucleotides to
Wnt-1 resulted in reduced cohesion of wound edge cells, abnormal protrusive activity, and random movement. Our data indicate that
Wnt-1 protein is present in postdevelopmental endothelial cells where it associates with cytoskeletal elements and may retain function as a tissue polarity gene.