title: A conserved tetraspanin subfamily promotes Notch signaling in Caenorhabditis elegans and in human cells.
abstract: The cytosolic domain of Notch is a membrane-tethered transcription factor. Ligand binding ultimately leads to gamma-secretase cleavage within the transmembrane domain, allowing the intracellular domain to translocate to the nucleus and activate target gene transcription. Constitutive Notch signaling has been associated with human cancers such as T cell acute lymphoblastic leukemia (T-ALL). As tetraspanins have been implicated in many different signaling processes, we assessed their potential contribution to Notch signaling. We used a genetic assay in Caenorhabditis elegans to identify TSP-12 as a positive factor for Notch activity in several cellular contexts. Then, using a cell culture system, we showed that two human TSP-12 orthologs, TSPAN33 and TSPAN5, promote Notch activity and are likely to act at the gamma-secretase cleavage step. We also acquired evidence for functional redundancy among tetraspanins in both C. elegans and human cells. Selective inhibition of tetraspanins may constitute an anti-NOTCH therapeutic approach to reduce gamma-secretase activity.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Institute for Cancer Genetics, USA.
authors.forename: Cory D
authors.initials: CD
authors.lastname: Dunn
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Sulis
authors.forename: Adolfo A
authors.initials: AA
authors.lastname: Ferrando
authors.forename: Iva
authors.initials: I
authors.lastname: Greenwald
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D005854:Germ Cells / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D059470:Tetraspanins
chemical_list: D015703:Antigens, CD; C554798:CD81 protein, human; C554869:CD9 protein, human; D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; D051880:Receptors, Notch; C505521:TSPAN33 protein, human; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D059470:Tetraspanins; C500304:tsp-15 protein, C elegans; D053829:Amyloid Precursor Protein Secretases