Too much EGF receptor signaling increases P compartment size (left). Too little reduces it (right).
PARKER/ELSEVIER
Correct organ size is measured in mass, not cell numbers—forcing or blocking cell division generally does not change an organ's overall dimensions. Parker found the same is true in the fly embryonic P compartment, which forms part of the larval epidermis. Increases in P compartment cell numbers were countered by more apoptosis and smaller cells. With fewer numbers, on the other hand, each cell grew larger to accommodate for their missing comrades.
In looking for a molecular explanation, Parker figured it would make sense to “have size information encoded right there in the patterning system” that also controls cell fate and positioning. For...
