Cooperative regulation of AJM-1 controls junctional integrity in Caenorhabditis elegans epithelia.
The function of epithelial cell sheets depends on the integrity of specialized cell-cell junctions that connect neighbouring cells. We have characterized the novel coiled-coil protein AJM-1, which localizes to an apical junctional domain of Caenorhabditis elegans epithelia basal to the HMR-HMP (cadherin-catenin) complex. In the absence of AJM-1, the integrity of this domain is compromised. Proper AJM-1 localization requires LET-413 and DLG-1, homologues of the Drosophila tumour suppressors Scribble and Discs large, respectively. DLG-1 physically interacts with AJM-1 and is required for its normal apical distribution, and LET-413 mediates the rapid accumulation of both DLG-1 and AJM-1 in the apical domain. In the absence of both dlg-1 and let-413 function AJM-1 is almost completely lost from apical junctions in embryos, whereas HMP-1 (alpha-catenin) localization is only mildly affected. We conclude that LET-413 and DLG-1 cooperatively control AJM-1 localization and that AJM-1 controls the integrity of a distinct apical junctional domain in C. elegans.
Köppen
M
M
Program in Cellular and Molecular Biology, University of Wisconsin-Madison, 1117 West Johnson Street, Madison, Wisconsin 53706, USA.
Simske
J S
JS
Sims
P A
PA
Firestein
B L
BL
Hall
D H
DH
Radice
A D
AD
Rongo
C
C
Hardin
J D
JD
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity / Q000502:physiology; D018076:DNA, Complementary; D004847:Epithelial Cells; D015801:Helminth Proteins / Q000378:metabolism; D007365:Intercellular Junctions / Q000502:physiology*; D008969:Molecular Sequence Data
C441580:AJM-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D015801:Helminth Proteins; C413362:LET-413 protein, C elegans