title: Sara endosomes and the asymmetric division of intestinal stem cells.
abstract: Tissue homeostasis is maintained by adult stem cells, which self-renew and give rise to differentiating cells. The generation of daughter cells with different fates is mediated by signalling molecules coming from an external niche or being asymmetrically dispatched between the two daughters upon stem cell mitosis. In the adult Drosophila midgut, the intestinal stem cell (ISC) divides to generate a new ISC and an enteroblast (EB) differentiating daughter. Notch signalling activity restricted to the EB regulates intestinal cell fate decision. Here, we show that ISCs divide asymmetrically, and Sara endosomes in ISCs are specifically dispatched to the presumptive EB. During ISC mitosis, Notch and Delta traffic through Sara endosomes, thereby contributing to Notch signalling bias, as revealed in Sara mutants: Sara itself contributes to the control of the ISC asymmetric division. Our data uncover an intrinsic endosomal mechanism during ISC mitosis, which participates in the maintenance of the adult intestinal lineage.
authors.affiliation: Department of Biochemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: Chrystelle
authors.initials: C
authors.lastname: Montagne
authors.forename: Marcos
authors.initials: M
authors.lastname: Gonzalez-Gaitan
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D002455:Cell Division / Q000502:physiology*; D019070:Cell Lineage / Q000235:genetics; D016764:Cell Polarity / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008938:Mitosis / Q000502:physiology; D021381:Protein Transport / Q000235:genetics; D051880:Receptors, Notch / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; D016212:Transforming Growth Factor beta; C064045:delta protein; C515087:sara protein, Drosophila
keywords: Intestinal stem cells; Notch signalling; Sara endosomes