Epidermal Induction by Wnt and BMP Requires Multivesicular Endosomes

PEREZ, BRIAN S.; PLOPER, DIEGO; DE ROBERTIS, EDWARD M.

Jornada; Biological Chemistry Retreat; 2013

University of California, Los Angeles

The BMP and Wnt pathways play an important role in the development of epidermis. Wnt signaling stabilizes transcription factors responsible for transducing BMP signals Smad1/5/8, since they contain conserved Glycogen Synthase Kinase 3 (GSK3) phosphorylation sites. Wnt stabilizes Smad1 and elicits epidermal induction. Wnt signaling inhibits GSK3 by sequestering it in multivesicular bodies (MVBs), separating it from its cytosolic substrates. Conclusions: 1) HRS and Rab7 MO inhibit the epidermal induction mediated by Wnt signaling. 2) Loss of HRS, Rab7, and Vps4 function inhibit epidermal induction mediated by the BMP pathway.We conclude that MVB formation is important for epidermal induction. Future Directions: Investigate the requirement of the Wnt effector beta-Catenin in epidermal induction using beta-catenin MOs to test if epidermis is induced when MVBs and GSK3 are both inhibited.