The heterotaxy gene GALNT11 glycosylates Notch to orchestrate cilia type and laterality.
Heterotaxy is a disorder of left-right body patterning, or laterality, that is associated with major congenital heart disease. The aetiology and mechanisms underlying most cases of human heterotaxy are poorly understood. In vertebrates, laterality is initiated at the embryonic left-right organizer, where motile cilia generate leftward flow that is detected by immotile sensory cilia, which transduce flow into downstream asymmetric signals. The mechanism that specifies these two cilia types remains unknown. Here we show that the N-acetylgalactosamine-type O-glycosylation enzyme GALNT11 is crucial to such determination. We previously identified GALNT11 as a candidate disease gene in a patient with heterotaxy, and now demonstrate, in Xenopus tropicalis, that galnt11 activates Notch signalling. GALNT11 O-glycosylates human NOTCH1 peptides in vitro, thereby supporting a mechanism of Notch activation either by increasing ADAM17-mediated ectodomain shedding of the Notch receptor or by modification of specific EGF repeats. We further developed a quantitative live imaging technique for Xenopus left-right organizer cilia and show that Galnt11-mediated Notch1 signalling modulates the spatial distribution and ratio of motile and immotile cilia at the left-right organizer. galnt11 or notch1 depletion increases the ratio of motile cilia at the expense of immotile cilia and produces a laterality defect reminiscent of loss of the ciliary sensor Pkd2. By contrast, Notch overexpression decreases this ratio, mimicking the ciliopathy primary ciliary dyskinesia. Together our data demonstrate that Galnt11 modifies Notch, establishing an essential balance between motile and immotile cilia at the left-right organizer to determine laterality, and reveal a novel mechanism for human heterotaxy.
1] Program in Vertebrate Developmental Biology, Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA [2] [3] Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USA.
Marko T
MT
Boskovski
1] Program in Vertebrate Developmental Biology, Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA [2].
Shiaulou
S
Yuan
Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Building 24.6.30, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
Nis Borbye
NB
Pedersen
Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Building 24.6.30, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
Christoffer Knak
CK
Goth
Program in Vertebrate Developmental Biology, Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA.
Svetlana
S
Makova
Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Building 24.6.30, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
Henrik
H
Clausen
Program in Vertebrate Developmental Biology, Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA.
Martina
M
Brueckner
Program in Vertebrate Developmental Biology, Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA.
Mustafa K
MK
Khokha
D051722:ADAM Proteins / Q000378:metabolism; D000072198:ADAM17 Protein; D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D002923:Cilia / Q000378:metabolism / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D006031:Glycosylation; D059446:Heterotaxy Syndrome / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D051881:Receptor, Notch1 / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014981:Xenopus / Q000196:embryology / Q000235:genetics; D029867:Xenopus Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
D010446:Peptide Fragments; D051881:Receptor, Notch1; D029867:Xenopus Proteins; C553205:GALNT11 protein, human; D017350:N-Acetylgalactosaminyltransferases; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606463:Adam17 protein, mouse