The Nkx5/HMX homeodomain protein MLS-2 is required for proper tube cell shape in the C. elegans excretory system

► MLS-2 is required for normal elongated cell shape of the C. elegans duct and pore epithelial tubes. ► MLS-2 cooperates with the EGF-Ras-ERK pathway to turn on lin-48/ovo during duct cell differentiation. ► mls-2 cell shape defects are more severe than those of lin-48/ovo mutants.