title: VICKZ proteins mediate cell migration via their RNA binding activity.
abstract: The highly conserved, RNA binding VICKZ proteins help regulate RNA localization, stability, and translation in many eukaryotes. These proteins are also required for cell migration in embryos and cultured cells. In adults, many tumors overexpress VICKZ homologs, and it has been hypothesized that the proteins can mediate cell motility and invasion. How these proteins facilitate cell movement and, in particular, whether their ability to bind RNA plays a role in their function remain unclear. Using HPLC and mass spectrometry to identify a region of Xenopus Vg1 RBP (xVICKZ3) that binds the vegetal localization element of Vg1 RNA, we generated a deletion construct that functions in a dominant-negative manner. The construct associates with full-length xVICKZ3 and severely reduces binding to target RNAs. This dominant-negative construct phenocopies the effect of down-regulating xVICKZ3 in Xenopus embryos. A corresponding deletion in the human homolog hVICKZ1 similarly functions in a dominant-negative fashion to reduce the ability of full-length hVICKZ protein to bind RNA. Expression of the dominant-negative construct in human carcinoma cells inhibits cell movement by several criteria. We conclude that the ability of VICKZ proteins to mediate cell migration, in vitro and in vivo, requires their RNA binding activity.
authors.affiliation: Department of Anatomy and Cell Biology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
authors.forename: Froma
authors.initials: F
authors.lastname: Oberman
authors.forename: Kinneret
authors.initials: K
authors.lastname: Rand
authors.forename: Yael
authors.initials: Y
authors.lastname: Maizels
authors.forename: Ariel M
authors.initials: AM
authors.lastname: Rubinstein
authors.forename: Joel K
authors.initials: JK
authors.lastname: Yisraeli
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D006801:Humans; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017384:Sequence Deletion; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis
chemical_list: C513103:GDF1 protein, Xenopus; C498635:IGF2BP3 protein, Xenopus; D016601:RNA-Binding Proteins; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins