title: Phosphorylation of DARPP-32 regulates breast cancer cell migration downstream of the receptor tyrosine kinase DDR1.
abstract: Cell migration plays a central role in processes such as development, wound healing and cancer metastasis. Here we describe a novel interaction between DDR1, a receptor tyrosine kinase activated by collagen, and the phosphoprotein DARPP-32 in mammary epithelial cells. DARPP-32 expression was readily detected in non-transformed mammary cell lines, but was strongly reduced or even absent in breast tumor cell lines, such as MCF7. Transfection of MCF7 cells with DARPP-32 resulted in severely impaired cell migration, while DARPP-32 transfection into the DDR1-deficient breast cancer cell line MDA-MB-231 did not alter migration. Co-expression of both DDR1 and DARPP-32 in MDA-MB-231 cells inhibited migration, thereby supporting a critical role of the DDR1/DARPP-32 complex in motility. Mutational substitution of the phosphorylation sites Thr-34 or Thr-75 on DARPP-32 revealed that phosphorylation of Thr-34 is necessary for the ability of DARPP-32 to impair breast tumor cell migration. Thus, DARPP-32 signaling downstream of DDR1 is a potential new target for effective anti-metastatic breast cancer therapy.
authors.affiliation: Experimental Pathology from the Department of Laboratory Medicine, Lund University, University Hospital Malmö, 205 02 Malmö, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Hansen
authors.forename: Paul
authors.initials: P
authors.lastname: Greengard
authors.forename: Angus C
authors.initials: AC
authors.lastname: Nairn
authors.forename: Tommy
authors.initials: T
authors.lastname: Andersson
authors.forename: Wolfgang F
authors.initials: WF
authors.lastname: Vogel
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D000070819:Discoidin Domain Receptor 1; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000378:metabolism*; D004847:Epithelial Cells / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; C092030:DDR1 protein, human; D000070819:Discoidin Domain Receptor 1; D020794:Receptor Protein-Tyrosine Kinases