Mutational analysis supports a core role for Drosophila α-catenin in adherens junction function

• Published in: Journal of cell science Vol. 125; no. Pt 1; pp. 233 - 245
• Main Authors: Sarpal, Ritu, Pellikka, Milena, Patel, Ridhdhi R, Hui, Felix Yan Wai, Godt, Dorothea, Tepass, Ulrich
• Format: Journal Article
• Language: English
• Published: England 01.01.2012
• Subjects: Actin-Related Protein 2-3 Complex - genetics; Actin-Related Protein 2-3 Complex - metabolism; Adherens Junctions - genetics; Adherens Junctions - metabolism; alpha Catenin - deficiency; alpha Catenin - genetics; alpha Catenin - metabolism; Animals; Armadillo Domain Proteins - genetics; Armadillo Domain Proteins - metabolism; Cadherins - metabolism; Drosophila melanogaster - cytology; Drosophila melanogaster - genetics; Drosophila melanogaster - growth & development; Drosophila melanogaster - metabolism; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Embryo, Nonmammalian - cytology; Embryo, Nonmammalian - embryology; Embryo, Nonmammalian - metabolism; Embryonic Development - genetics; Female; Gene Deletion; Head - growth & development; Imaginal Discs - metabolism; Larva - growth & development; Male; Mutagenesis; Oogenesis - genetics; Ovarian Follicle - cytology; Ovarian Follicle - metabolism; Phenotype; Spectrin - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Zygote - metabolism
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.096644

α-catenin associates the cadherin-catenin complex with the actin cytoskeleton. α-catenin binds to β-catenin, which links it to the cadherin cytoplasmic tail, and F-actin, but also to a multitude of actin-associated proteins. These interactions suggest a highly complex cadherin-actin interface. Moreover, mammalian αE-catenin has been implicated in a cadherin-independent cytoplasmic function in Arp2/3-dependent actin regulation, and in cell signaling. The function and regulation of individual molecular interactions of α-catenin, in particular during development, are not well understood. We have generated mutations in Drosophila α-Catenin (α-Cat) to investigate α-Catenin function in this model, and to establish a setup for testing α-Catenin-related constructs in α-Cat-null mutant cells in vivo. Our analysis of α-Cat mutants in embryogenesis, imaginal discs and oogenesis reveals defects consistent with a loss of cadherin function. Compromising components of the Arp2/3 complex or its regulator SCAR ameliorate the α-Cat loss-of-function phenotype in embryos but not in ovaries, suggesting negative regulatory interactions between α-Catenin and the Arp2/3 complex in some tissues. We also show that the α-Cat mutant phenotype can be rescued by the expression of a DE-cadherin::α-Catenin fusion protein, which argues against an essential cytosolic, cadherin-independent role of Drosophila α-Catenin.