The periciliary ring in polarized epithelial cells is a hot spot for delivery of the apical protein gp135.
In polarized epithelial cells, newly synthesized cell surface proteins travel in carrier vesicles from the trans Golgi network to the apical or basolateral plasma membrane. Despite extensive research on polarized trafficking, the sites of protein delivery are not fully characterized. Here we use the SNAP tag system to examine the site of delivery of the apical glycoprotein gp135. We show that a cohort of gp135 is delivered to a ring surrounding the base of the primary cilium, followed by microtubule-dependent radial movement away from the cilium. Delivery to the periciliary ring was specific to newly synthesized and not recycling protein. A subset of this newly delivered protein traverses the basolateral membrane en route to the apical membrane. Crumbs3a, another apical protein, was not delivered to the periciliary region, instead making its initial apical appearance in a pattern that resembled its steady-state distribution. Our results demonstrate a surprising "hot spot" for gp135 protein delivery at the base of the primary cilium and suggest the existence of a novel microtubule-based directed movement of a subset of apical surface proteins.
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520.
Emily H
EH
Stoops
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520.
Michael
M
Hull
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520.
Christina
C
Olesen
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520.
Kavita
K
Mistry
Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109.
Jennifer L
JL
Harder
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.
Felix
F
Rivera-Molina
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.
Derek
D
Toomre
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520 michael.caplan@yale.edu.
Michael J
MJ
Caplan
D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D002923:Cilia / Q000378:metabolism*; D058967:Contactin 1 / Q000378:metabolism*; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D008562:Membrane Glycoproteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D021381:Protein Transport; D013194:Staining and Labeling; D021601:trans-Golgi Network / Q000378:metabolism
C472002:CRB3 protein, human; D058967:Contactin 1; D008562:Membrane Glycoproteins