Drosophila alpha-catenin and E-cadherin bind to distinct regions of Drosophila Armadillo.
Adherens junctions are multiprotein complexes mediating cell-cell adhesion and communication. They are organized around a transmembrane cadherin, which binds a set of cytoplasmic proteins required for adhesion and to link the complex to the actin cytoskeleton. Three components of Drosophila adherens junctions, analogous to those in vertebrates, have been identified: Armadillo (homolog of beta-catenin), Drosophila E-cadherin (DE-cadherin), and alpha-catenin. We carried out the first analysis of the interactions between these proteins using in vitro binding assays, the yeast two-hybrid system, and in vivo assays. We identified a 76-amino acid region of Armadillo that is necessary and sufficient for binding alpha-catenin and found that the N-terminal 258 amino acids of alpha-catenin interact with Armadillo. A large region of Armadillo, spanning six central Armadillo repeats, is required for DE-cadherin binding, whereas only 41 amino acids of the DE-cadherin cytoplasmic tail are sufficient for Armadillo binding. Our data complement and extend results obtained in studies of vertebrate adherens junctions, providing a foundation for understanding how junctional proteins assemble and a basis for interpreting existing mutations and creating new ones.
Pai
L M
LM
Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA.
Kirkpatrick
C
C
Blanton
J
J
Oda
H
H
Takeichi
M
M
Peifer
M
M
D000595:Amino Acid Sequence; D000818:Animals; D051186:Armadillo Domain Proteins; D001665:Binding Sites; D015820:Cadherins / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D007301:Insect Hormones / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D017354:Point Mutation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D013329:Structure-Activity Relationship; D015534:Trans-Activators; D014157:Transcription Factors; D051178:alpha Catenin
C495305:ARM protein, Drosophila; D051186:Armadillo Domain Proteins; D015820:Cadherins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D007301:Insect Hormones; D011506:Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051178:alpha Catenin