Par3 functions in the biogenesis of the primary cilium in polarized epithelial cells.
Par3 is a PDZ protein important for the formation of junctional complexes in epithelial cells. We have identified an additional role for Par3 in membrane biogenesis. Although Par3 was not required for maintaining polarized apical or basolateral membrane domains, at the apical surface, Par3 was absolutely essential for the growth and elongation of the primary cilium. The activity reflected its ability to interact with kinesin-2, the microtubule motor responsible for anterograde transport of intraflagellar transport particles to the tip of the growing cilium. The Par3 binding partners Par6 and atypical protein kinase C interacted with the ciliary membrane component Crumbs3 and we show that the PDZ binding motif of Crumbs3 was necessary for its targeting to the ciliary membrane. Thus, the Par complex likely serves as an adaptor that couples the vectorial movement of at least a subset of membrane proteins to microtubule-dependent transport during ciliogenesis.
Sfakianos
Jeff
J
Department of Cell Biology, Ludwig Institute for Cancer Research, New Haven, CT 06520.
Togawa
Akashi
A
Maday
Sandra
S
Hull
Mike
M
Pypaert
Marc
M
Cantley
Lloyd
L
Toomre
Derek
D
Mellman
Ira
I
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism* / Q000648:ultrastructure; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D054731:PDZ Domains; D016415:Sequence Alignment
D008565:Membrane Proteins