Ninein is essential for apico-basal microtubule formation and CLIP-170 facilitates its redeployment to non-centrosomal microtubule organizing centres.
Differentiation of columnar epithelial cells involves a dramatic reorganization of the microtubules (MTs) and centrosomal components into an apico-basal array no longer anchored at the centrosome. Instead, the minus-ends of the MTs become anchored at apical non-centrosomal microtubule organizing centres (n-MTOCs). Formation of n-MTOCs is critical as they determine the spatial organization of MTs, which in turn influences cell shape and function. However, how they are formed is poorly understood. We have previously shown that the centrosomal anchoring protein ninein is released from the centrosome, moves in a microtubule-dependent manner and accumulates at n-MTOCs during epithelial differentiation. Here, we report using depletion and knockout (KO) approaches that ninein expression is essential for apico-basal array formation and epithelial elongation and that CLIP-170 is required for its redeployment to n-MTOCs. Functional inhibition also revealed that IQGAP1 and active Rac1 coordinate with CLIP-170 to facilitate microtubule plus-end cortical targeting and ninein redeployment. Intestinal tissue andin vitroorganoids from theClip1/Clip2double KO mouse with deletions in the genes encoding CLIP-170 and CLIP-115, respectively, confirmed requirement of CLIP-170 for ninein recruitment to n-MTOCs, with possible compensation by other anchoring factors such as p150Gluedand CAMSAP2 ensuring apico-basal microtubule formation despite loss of ninein at n-MTOCs.
School of Biological Sciences, University of East Anglia, Norwich, UK.
Deborah A
DA
Goldspink
School of Computing Science, University of East Anglia, Norwich, UK.
Chris
C
Rookyard
School of Biological Sciences, University of East Anglia, Norwich, UK.
Benjamin J
BJ
Tyrrell
School of Biological Sciences, University of East Anglia, Norwich, UK.
Jonathan
0000-0001-7986-4917
J
Gadsby
School of Biological Sciences, University of East Anglia, Norwich, UK.
James
J
Perkins
School of Biological Sciences, University of East Anglia, Norwich, UK.
Elizabeth K
EK
Lund
Department of Cell Biology and Genetics, Erasmus MC, Rotterdam, The Netherlands.
Niels
N
Galjart
School of Biological Sciences, University of East Anglia, Norwich, UK.
Paul
P
Thomas
Medical School, University of East Anglia, Norwich, UK.
Tom
T
Wileman
School of Biological Sciences, University of East Anglia, Norwich, UK m.mogensen@uea.ac.uk.
Mette M
0000-0002-8965-1592
MM
Mogensen
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D016764:Cell Polarity; D048430:Cell Shape; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism*; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology; D055786:Gene Knockout Techniques; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D022101:Microtubule-Organizing Center / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*
D003598:Cytoskeletal Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; C076744:cytoplasmic linker protein 170
CLIP-170; IQGAP1; Rac1; microtubules; ninein; non-centrosomal MTOCs