Jeffrey R. Miller

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The serine/threonine kinase Xgsk-3 and the intracellular protein beta-catenin are necessary for the establishment of the dorsal-ventral axis in Xenopus. Although genetic evidence from Drosophila indicates that Xgsk-3 is upstream of beta-catenin, direct interactions between these proteins have not been demonstrated. We demonstrate that phosphorylation of(More)
In Drosophila, planar cell polarity (PCP) signaling is mediated by the receptor Frizzled (Fz) and transduced by Dishevelled (Dsh). Wingless (Wg) signaling also requires Dsh and may utilize DFz2 as a receptor. Using a heterologous system, we show that Dsh is recruited selectively to the membrane by Fz but not DFz2, and this recruitment depends on the DEP(More)
Members of the vertebrate Wnt family have been subdivided into two functional classes according to their biological activities. Some Wnts signal through the canonical Wnt-1/wingless pathway by stabilizing cytoplasmic beta-catenin. By contrast other Wnts stimulate intracellular Ca2+ release and activate two kinases, CamKII and PKC, in a G-protein-dependent(More)
Communication between cells is often mediated by secreted signaling molecules that bind cell surface receptors and modulate the activity of specific intracellular effectors. The Wnt family of secreted glycoproteins is one group of signaling molecules that has been shown to control a variety of developmental processes including cell fate specification, cell(More)
Dapper was isolated in a screen for proteins interacting with Dishevelled, a key factor in Wnt signaling. Dapper and Dishevelled colocalize intracellularly and form a complex with Axin, GSK-3, CKI, and beta-catenin. Overexpression of Dapper increases Axin and GSK-3 in this complex, resulting in decreased soluble beta-catenin and decreased activation of(More)
Examination of the subcellular localization of Dishevelled (Dsh) in fertilized Xenopus eggs revealed that Dsh is associated with vesicle-like organelles that are enriched on the prospective dorsal side of the embryo after cortical rotation. Dorsal enrichment of Dsh is blocked by UV irradiation of the vegetal pole, a treatment that inhibits development of(More)
β-catenin is thought to mediate cell fate specification events by localizing to the nucleus where it modulates gene expression. To ask whether β-catenin is involved in cell fate specification during sea urchin embryogenesis, we analyzed the distribution of nuclear β-catenin in both normal and experimentally manipulated embryos. In unperturbed embryos,(More)
BACKGROUND Wnts are secreted proteins implicated in cell-cell interactions during embryogenesis and tumorigenesis, but receptors involved in transducing Wnt signals have not yet been definitively identified. Members of a large family of putative transmembrane receptors homologous to the frizzled protein in Drosophila have been identified recently in both(More)
Eggs of Xenopus laevis undergo a postfertilization cortical rotation that specifies the position of the dorso-ventral axis and activates a transplantable dorsal-determining activity in dorsal blastomeres by the 32-cell stage. There have heretofore been no reported dorso-ventral asymmetries in endogenous signaling proteins that may be involved in this(More)