title: E-cadherin is required for centrosome and spindle orientation in Drosophila male germline stem cells.
abstract: Many adult stem cells reside in a special microenvironment known as the niche, where they receive essential signals that specify stem cell identity. Cell-cell adhesion mediated by cadherin and integrin plays a crucial role in maintaining stem cells within the niche. In Drosophila melanogaster, male germline stem cells (GSCs) are attached to niche component cells (i.e., the hub) via adherens junctions. The GSC centrosomes and spindle are oriented toward the hub-GSC junction, where E-cadherin-based adherens junctions are highly concentrated. For this reason, adherens junctions are thought to provide a polarity cue for GSCs to enable proper orientation of centrosomes and spindles, a critical step toward asymmetric stem cell division. However, understanding the role of E-cadherin in GSC polarity has been challenging, since GSCs carrying E-cadherin mutations are not maintained in the niche. Here, we tested whether E-cadherin is required for GSC polarity by expressing a dominant-negative form of E-cadherin. We found that E-cadherin is indeed required for polarizing GSCs toward the hub cells, an effect that may be mediated by Apc2. We also demonstrated that E-cadherin is required for the GSC centrosome orientation checkpoint, which prevents mitosis when centrosomes are not correctly oriented. We propose that E-cadherin orchestrates multiple aspects of stem cell behavior, including polarization of stem cells toward the stem cell-niche interface and adhesion of stem cells to the niche supporting cells.
authors.affiliation: Center for Stem Cell Biology, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Mayu
authors.initials: M
authors.lastname: Inaba
authors.forename: Hebao
authors.initials: H
authors.lastname: Yuan
authors.forename: Viktoria
authors.initials: V
authors.lastname: Salzmann
authors.forename: Margaret T
authors.initials: MT
authors.lastname: Fuller
authors.forename: Yukiko M
authors.initials: YM
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion; D016764:Cell Polarity; D018385:Centrosome / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology*; D005786:Gene Expression Regulation; D008297:Male; D021381:Protein Transport; D013094:Spermatozoa / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: C467323:APC2 protein, Drosophila; D015820:Cadherins; D029721:Drosophila Proteins; D025521:Tumor Suppressor Proteins
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