title: Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis.
abstract: BACKGROUND
  CAP/Capulet (Capt), Slingshot (Ssh) and Cofilin/Twinstar (Tsr) are actin-binding proteins that restrict actin polymerization. Previously, it was shown that low resolution analyses of loss-of-function mutations in capt, ssh and tsr all show ectopic F-actin accumulation in various Drosophila tissues. In contrast, RNAi depletion of capt, tsr and ssh in Drosophila S2 cells all affect actin-based lamella formation differently. Whether loss of these three related genes might cause the same effect in the same tissue remains unclear.
  
  
  METHODS
  Loss-of-function mutant clones were generated using the MARCM or EGUF system whereas overexpression clones were generated using the Flip-out system. Immunostaining were then performed in eye imaginal discs with clones. FRAP was performed in cultured eye discs.
  
  
  RESULTS
  Here, we compared their loss-of-function phenotype at single-cell resolution, using a sheet of epithelial cells in the Drosophila eye imaginal disc as a model system. Surprisingly, we found that capt and ssh, but not tsr, mutant cells within and posterior to the morphogenetic furrow (MF) shared similar phenotypes. The capt/ssh mutant cells possessed: (1) hexagonal cell packing with discontinuous adherens junctions; and (2) largely complementary accumulation of excessive phosphorylated myosin light chain (p-MLC) and F-actin rings at the apical cortex. We further showed that the capt/ssh mutant phenotypes depended on the inactivation of protein kinase A (PKA) and activation of Rho.
  
  
  CONCLUSIONS
  Although Capt, Ssh and Tsr were reported to negatively regulate actin polymerization, we found that Capt and Ssh, but not Tsr, share overlapping functions during eye morphogenesis.
authors.affiliation: Institute of Molecular Medicine, Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30034, Republic of China.
authors.forename: Chiao-Ming
authors.initials: CM
authors.lastname: Lin
authors.forename: Pei-Yi
authors.initials: PY
authors.lastname: Lin
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Li
authors.forename: Jui-Chou
authors.initials: JC
authors.lastname: Hsu
mesh_terms: D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000737:chemistry / Q000378:metabolism; D022005:Adherens Junctions / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000254:growth & development; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005123:Eye / Q000254:growth & development / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis / Q000235:genetics*; D009154:Mutation; D009924:Organ Culture Techniques; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D034622:RNA Interference
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; C410502:Capt protein, Drosophila; D029721:Drosophila Proteins; D008840:Microfilament Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; C448559:ssh protein, Drosophila; D010749:Phosphoprotein Phosphatases