Figure 6.

Damaged or slow-growing disks signal to the other tissues to reduce their growth and prolong development. Damaged or slow-growing disks signal their status within the tissue by upregulating stress signaling via the JNK pathway and the apoptotic machinery protein p53. They signal their slow growth to the rest of the body, at least in part, through retinoid signaling and potentially through Neural Lazarillo (NLaz). This reduces ecdysone synthesis by the prothoracic gland (top tissue in box), reduces growth of another normally growing disks (leg disk in middle), and reduces PTTH (PTTH cells in yellow) and may reduce the production of insulin like peptides (dILP) from the insulin producing cells (in red) in the brain (bottom tissue). In this manner, growth-perturbed disks delay development although the larvae eventually metamorphose to produce normally sized adults.