title: Effects of src kinase and TGFbeta1 on the differentiation and morphogenesis of MDCK cells grown in three-dimensional collagen and Matrigel environments.
abstract: This study attempted to analyse in detail the effect of src kinase on the growth and differentiation of MDCK cells in different extracellular matrix (ECM) environments. A method was developed to label the membrane proteins in situ and the distribution of cytoskeletal and junctional proteins was visualized in three-dimensional cell complexes, using optical sections generated by confocal microscopy. Independently of the ECM, non-transformed MDCK cells formed differentiated cell cysts with one or a few lumina, with the apical side facing the lumen; ZO-1 was expressed at the tight junctions close to the apical side and beta-catenin, E-cadherin and fodrin along the entire lateral walls. The phenotype of src kinase activated MDCK cells was strongly dependent on the ECM and varied from an irregular cluster in collagen I, to tubular structures in laminin or proteoglycans, and finally to a polarized cell cyst in Matrigel. In collagen I, E-cadherin and beta-catenin were seen partially along the lateral walls and partially in the cytoplasm of src-transformed MDCK cells; fodrin was released into the cytoplasm and ZO-1 was not visualized. When the src-transformed cells were cultivated in Matrigel, their junctional proteins were recruited to the cell membranes and ZO-1 reappeared at the apical face. Thus, the components of Matrigel could overcome the deleterious effect of src on the polarity of MDCK cells. TGFbeta1, together with its receptors and other soluble factors in Matrigel, were responsible for the induction of differentiation. The results show that tyrosine phosphorylation sensitizes the epithelial MDCK cells to ECM and TGFbeta1.
authors.affiliation: Biocenter Oulu and the Department of Pathology, University of Oulu, FIN-90014 University of Oulu, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Rahikkala
authors.forename: R
authors.initials: R
authors.lastname: Sormunen
authors.forename: S
authors.initials: S
authors.lastname: Eskelinen
mesh_terms: D015820:Cadherins / Q000032:analysis / Q000378:metabolism; D002352:Carrier Proteins / Q000032:analysis / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D003094:Collagen; D024042:Collagen Type I; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000378:metabolism; D004338:Drug Combinations; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D005782:Gels; D006493:Heparin / Q000031:analogs & derivatives*; D006801:Humans; D007797:Laminin; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D008840:Microfilament Proteins / Q000032:analysis / Q000378:metabolism; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism; D011509:Proteoglycans; D015534:Trans-Activators; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D019061:src-Family Kinases / Q000032:analysis / Q000378:metabolism*; D013049:Spectrin
chemical_list: D015820:Cadherins; D002352:Carrier Proteins; D003094:Collagen; D024042:Collagen Type I; D003598:Cytoskeletal Proteins; D004338:Drug Combinations; D005782:Gels; D006493:Heparin; D007797:Laminin; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011509:Proteoglycans; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D019061:src-Family Kinases; D013049:Spectrin; C495270:CTNNB1 protein, human; C569042:TJP1 protein, human; C036090:heparin proteoglycan; C059485:matrigel