Evolution of the Wnt Pathways

Abstract

Wnt proteins mediate the transduction of at least three major signaling pathways that play central roles in many early and late developmental decisions. They control diverse cellular behaviors, such as cell fate decisions, proliferation, and migration, and are involved in many important embryological events, including axis specification, gastrulation, and limb, heart, or neural development. The three major Wnt pathways are activated by ligands, the Wnts, which clearly belong to the same gene family. However, their signal is then mediated by three separate sets of extracellular, cytoplasmic, and nuclear components that are pathway-specific and that distinguish each of them. Homologs of the Wnt genes and of the Wnt pathways components have been discovered in many eukaryotic model systems and functional investigations have been carried out for most of them. This review extracts available data on the Wnt pathways, from the protist Dictyostelium discoideum to humans, and provides from an evolutionary prospective the overall molecular and functional conservation of the three Wnt pathways and their activators throughout the eukaryotic superkingdom.

Role of the Wnt/β-catenin pathway in gastric cancer: An in-depth literature review

“…The Wnt signaling pathways, named for its ligands Drosophila wingless (wg) and the mouse homolog Int-1 (Wnt-1) [11] , are a group of signal transduction pathways which play a fundamental role in the cell fate specification during early embryonic development, proliferation, body axis patterning, survival, apoptosis, and in tissue homeostasis in adults [12] . Wnt signaling pathways can be activated upon binding of Wnt ligands (19 known members in humans) to their cell surface receptor complex, which includes 10 different members of the Frizzled (Fz) family of atypical heptahelical G-protein-coupled receptors [13][14][15] .…”

Molecular networks in skeletal muscle plasticity

“…From an evolutionary perspective we can surmise that the pathways outlined in Figs 1 and 2 involved in skeletal muscle plasticity, as incomplete and premature as they may be, are highly conserved among animal species (Croce and McClay, 2009). Much of the research on muscle signaling has been done in genetically engineered mice and in C2C12 muscle cell cultures (derived from mice).…”

The Evolution of the Wnt Pathway

“…Wnt signaling controls a variety of different cellular behaviors including cell proliferation, stem cell maintenance and differentiation, coordinated cell movement, and the establishment of tissue polarity (Croce and McClay 2008;van Amerongen and Nusse 2009 It is difficult to judge which of the Wnt functions might represent the ancestral form-the b-catenin dependent or independent-or how this might be related to the specific structure of Wnt ligands. There are hints that canonical and noncanonical functions of Wnt proteins may be conserved during evolution (Rigo-Watermeier et al 2011), but the distinction between both groups of ligands is not sharp (see above).…”

“…Because WntA was identified in the genome of echinoderms (Sodergren et al 2006;Croce and McClay 2008), the common ancestor of deuterostomes must have had a complete set of Wnt genes. Genome data suggest some Wnt gene loss in the cephalochordate amphioxus (Wnt2, -9, -16, and -A) (Putnam et al 2007) and the urochordate ascidian Ciona (Wnt8 and -11) (Dehal et al 2002).…”