title: Secretion of Wnt ligands requires Evi, a conserved transmembrane protein.
abstract: Wnt signaling pathways are important for multiple biological processes during development and disease. Wnt proteins are secreted factors that activate target-gene expression in both a short- and long-range manner. Currently, little is known about how Wnts are released from cells and which factors facilitate their secretion. Here, we identify a conserved multipass transmembrane protein, Evenness interrupted (Evi/Wls), through an RNAi survey for transmembrane proteins involved in Drosophila Wingless (Wg) signaling. During development, evi mutants have patterning defects that phenocopy wg loss-of-function alleles and fail to express Wg target genes. evi's function is evolutionarily conserved as depletion of its human homolog disrupts Wnt signaling in human cells. Epistasis experiments and clonal analysis place evi in the Wg-producing cell. Our results show that Wg is retained by evi mutant cells and suggest that evi is the founding member of a gene family specifically required for Wg/Wnt secretion.
authors: German Cancer Research Center, Boveri-Group Signaling and Functional Genomics, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
authors: Kerstin
authors: K
authors: Bartscherer
authors: Nadège
authors: N
authors: Pelte
authors: Dierk
authors: D
authors: Ingelfinger
authors: Michael
authors: M
authors: Boutros