FIGURE 4. Stages, pathways, and tissues involved in molting.

(A) Molts have been divided into three main stages: apolysis, cuticle synthesis, and ecdysis. Some genes may be involved in more than one stage. Proteases such as CPZ-1 are involved in apolysis. Ecdysis (separation of old cuticle) also involves a complex set of motor behaviors not depicted here. (B) Genetic pathways regulating molting. Highly speculative outline of possible regulatory relationships, partly based on ¹²⁶. Not all regulatory interactions may apply to all molts. (C) Tissue coordination during molts. The focus of LIN-42A function in molting appears to be in the lateral seam. LIN-42A might directly or indirectly regulate epidermal quiescence signals such as LIN-3 and OSM-7/11, which act on neurons. Quiescence involves decreased muscle contractions, which in turn may affect expression of epidermal molting genes ¹³⁵.