LIN-23-mediated degradation of beta-catenin regulates the abundance of GLR-1 glutamate receptors in the ventral nerve cord of C. elegans.

Ubiquitin-mediated protein degradation has been proposed to play an important role in regulating synaptic transmission. Here we show that LIN-23, the substrate binding subunit of a Skp1/Cullin/F Box (SCF) ubiquitin ligase, regulates the abundance of the glutamate receptor GLR-1 in the ventral nerve cord of C. elegans. Mutants lacking lin-23 had an increased abundance of GLR-1 in the ventral cord. The increase of GLR-1 was not caused by changes in the ubiquitination of GLR-1. Instead, SCF(LIN-23) regulates GLR-1 through the beta-catenin homolog BAR-1 and the TCF/Lef transcription factor homolog POP-1. We hypothesize that LIN-23-mediated degradation of BAR-1 beta-catenin regulates the transcription of Wnt target genes, which in turn alter postsynaptic properties.