RT Journal Article SR Electronic T1 The scaffolding protein Cnk Interacts with Alk to Promote Visceral Founder Cell Specification in Drosophila JF bioRxiv FD Cold Spring Harbor Laboratory SP 099986 DO 10.1101/099986 A1 Georg Wolfstetter A1 Kathrin Pfeifer A1 Jesper Ruben van Dijk A1 Fredrik Hugosson A1 Xiangyi Lu A1 Ruth Helen Palmer YR 2017 UL http://biorxiv.org/content/early/2017/01/12/099986.abstract AB In Drosophila, the receptor tyrosine kinase Alk and its ligand Jeb are required to drive founder cell (FC) specification in the visceral mesoderm (VM). Alk-signalling activates downstream MAPK/ERK- and PI3K-pathways in human and Drosophila but little is known about immediate downstream signalling events. Here we report that the scaffolding protein Cnk interacts directly with Alk via a novel c-terminal binding motif. Cnk is required for Alk-signalling as ectopic expression of the minimal interaction motif as well as loss of maternal and zygotic cnk blocks visceral FC-formation, resembling the phenotype of jeb and Alk mutants. We also show that the Cnk-interactor Aveugle/Hyphen (Ave/HYP) is critical, while the (pseudo-) kinase Ksr is not required for Alk-signalling in the developing VM. Taken together, Cnk and Ave represent the first molecules downstream of Alk whose loss genocopies the lack of visceral FC-specification of Alk and jeb mutants indicating an essential role in Alk-signalling.