Fig. 7

A two-step model for PVD dendrite development. 1) Guidance receptor complexes first recruit and activate the WRC, which in turn produces a branched actin network resulting in the formation of swellings. 2) The WRC (likely together with the branched actin network) recruits UNC-34 to the swellings through PRR-EVH1 interactions, which then, together with UNC-115, produce linear actin bundles to initiate filopodia outgrowth. UNC-34 continues to elongate actin filaments at the tips of filopodia. 3) As the new branch elongates, guidance receptor complexes can continue to recruit the WRC to the growth tip, causing pauses, new swellings, and new filopodia. 4) Filopodia are finally stabilized as new dendrites when guidance receptors bind to extracellular ligands, or retracted when ligands are not present