Fig. 9

Baf A1 and ALLM treatment restore melanophore morphology and survival using an autophagy independent mechanism.

A, B) Immunoblot analysis of LC3B II (A) and I (B) bands in control, Baf A1 and ALLM treated larvae lysates. A significant increase is detected in LC3B II in vps11^w66 larvae. We did not consistently observe an increase under Baf A1 and ALLM treatment conditions (see densitometry analysis). LC3B I levels were lower in mutants across treatments but not significantly different from control (1% DMSO or 0.01% ETOH) fish. Anti-pan cadherin was used as a loading control. C, D) Graphical representation of density analysis of LC3B II and LC3B I bands, respectively, from three immunoblots using Image J. Samples were analyzed via one way ANOVA with Bonferonni multiple comparison analysis (p<0.001**). Error bars are standard deviation. E) Model for vps11 function in melanosome maturation, trafficking and integrity. We propose that vps11 functions at dual locations to promote melanophore morphology and survival: 1) During melanogenesis to promote endosome/melanosome fusion and correct melanosome trafficking and maturation. 2) During autophagy to promote melanosome/lysosome/autophagosome fusion. When fusion does not occur at the latter step, organelle accumulation leads to the compromise of melanosome (and/or lysosome) integrity leading to increased cathepsin secretion and/or activity.