title: Ephrin-As, Eph receptors and integrin α3 interact and colocalise at membrane protrusions of U251MG glioblastoma cells.
abstract: Glioblastoma is the most common brain cancer. Ephrins and their Eph receptors play important roles in the development of central nervous system and the regulation of cancer cell migration and invasion. In a search for the Eph receptor complexes, we used tandem affinity purification based interaction screening with tagged ephrins A1, A3 and A4 combined with protein identification by mass-spectrometry in U251MG glioblastoma cells. Ephrins bound to Eph receptors, mainly to EphA2 in these cells. Integrin α3 was identified in protein complexes with ephrin-As. Soluble ephrin-A1 colocalised with integrin α3 at the cell surface, and was rapidly endocytosed by the cells. However, integrin α3 did not colocalise with internalised ephrin-A1, whereas EphA2 receptor did. In U251MG cells, integrin α3 colocalised with EphA2 receptor at the cell edges and protrusions. Sites of EphA2-integrin α3 colocalisation were positive for vinculin, focal adhesion kinase and phosphotyrosine, that is, markers for cell adhesion and active signalling. The interaction between ephrin-As, Eph receptors and integrin α3 is plausibly important for the crosstalk between Eph and integrin signalling pathways at the membrane protrusions and in the migration of brain cancer cells.
authors.affiliation: Department of Virology and Pathology, The Haartman Institute, Translational Cancer Biology Research Program, Helsinki, Finland.
authors.forename: Andrey
authors.initials: A
authors.lastname: Makarov
authors.forename: Irene
authors.initials: I
authors.lastname: Ylivinkka
authors.forename: Tuula A
authors.initials: TA
authors.lastname: Nyman
authors.forename: Marko
authors.initials: M
authors.lastname: Hyytiäinen
authors.forename: Jorma
authors.initials: J
authors.lastname: Keski-Oja
mesh_terms: D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D022081:Cell Surface Extensions / Q000378:metabolism*; D036342:Ephrins / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D039422:Integrin alpha3 / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D008024:Ligands; D011485:Protein Binding; D021381:Protein Transport; D011554:Pseudopodia / Q000378:metabolism; D036104:Receptor, EphA2 / Q000378:metabolism*; D012995:Solubility; D013997:Time Factors
chemical_list: D036342:Ephrins; D039422:Integrin alpha3; D008024:Ligands; D036104:Receptor, EphA2
keywords: Eph receptor; cell signalling; glioblastoma; integrin α3; mass spectrometry; tandem affinity purification