Figure 8. Model for function of cell adhesion protein interactions.

(A) Three pathways additively act to achieve the wild type level of HOA-AVG axon fasciculation. The median percentages of HOA-AVG axon fasciculation in mutant and/or PHC ablation studies were used to estimate contribution of each pathway. (B) Schematic showing axons, cell adhesion protein interactions, and their putative function during the L4-adult transition in males. In L4 stage, the PHC axon contacts the AVG axon through RIG-6-SAX-7S interaction. In adult stage, close apposition of HOA and AVG membranes involves CASY-1-BAM-2 interaction, while unidentified protein interaction may mediate contact between HOA and PHC. These protein interactions regulate the probability of axon fasciculation and vulva location behavior possibly by controlling synapse formation between the neurons.