Novel membrane protein shrew-1 targets to cadherin-mediated junctions in polarized epithelial cells.
While searching for potential candidate molecules relevant for the pathogenesis of endometriosis, we discovered a 2910-base pair cDNA encoding a novel putative 411-amino acid integral membrane protein that we called shrew-1. The putative open-reading frame was confirmed with antibodies against shrew-1 peptides that labeled a protein of approximately 48 kDa in extracts of shrew-1 mRNA-positive tissue and also detected ectopically expressed shrew-1. Expression of epitope-tagged shrew-1 in epithelial cells and analysis by surface biotinylation and immunoblots demonstrated that shrew-1 is indeed a transmembrane protein. Shrew-1 is able to target to E-cadherin-mediated adherens junctions and interact with the E-cadherin-catenin complex in polarized MCF7 and Madin-Darby canine kidney cells, but not with the N-cadherin-catenin complex in nonpolarized epithelial cells. Direct interaction of shrew-1 with beta-catenin in in vitro pull-down assay suggests that beta-catenin might be one of the proteins that targets and/or retains shrew-1 in the adherens junctions. Interestingly, shrew-1 was partially translocated in response to scatter factor (ligand of receptor tyrosine kinase c-met) from the plasma membrane to the cytoplasm where it still colocalized with endogenous E-cadherin. In summary, we introduce shrew-1 as a novel component of adherens junctions, interacting with E-cadherin-beta-catenin complexes in polarized epithelial cells.
Bharti
Sanita
S
Humangenetik fuer Biologen, Johann Wolfgang Goethe-Universität, D-60054 Frankfurt, Germany.
Handrow-Metzmacher
Heike
H
Zickenheiner
Silvia
S
Zeitvogel
Andreas
A
Baumann
Rudolf
R
Starzinski-Powitz
Anna
A
D022005:Adherens Junctions / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D015815:Cell Adhesion Molecules; D016764:Cell Polarity / Q000502:physiology; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004285:Dogs; D004715:Endometriosis / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D015534:Trans-Activators / Q000378:metabolism*; D051176:beta Catenin
C483313:AJAP1 protein, human; C495270:CTNNB1 protein, human; D015820:Cadherins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D015534:Trans-Activators; D051176:beta Catenin