In:
Journal of Cell Science, The Company of Biologists
Abstract:
The establishment of epithelial polarity is tightly linked to the dramatic reorganization of microtubules (MTs) from a radial array to a vertical alignment of non-centrosomal MT bundles along the lateral membrane and a meshwork under the apical and basal membranes. However, little is known about the underlying molecular mechanism of this polarity-dependent MT remodeling. The evolutionarily conserved cell polarity-regulating kinase PAR-1, whose activity is essential for maintaining the dynamic state of MTs, plays indispensable roles to promote this process. Here, we identify a novel PAR-1-binding protein, named MTCL1 (Microtubule crosslinking factor 1), which crosslinks MTs through its N-terminal MT-binding region and subsequent coiled-coil motifs. MTCL1 colocalized with the apicobasal MT bundles in epithelial cells, and its knockdown impaired the development of these MT bundles and the epithelial cell specific columnar shape. Rescue experiments revealed that the N-terminal MT-binding region was indispensable for restoring these defects of the knockdown cells. MT regrowth assays indicated that MTCL1 was not required for the initial radial growth of MTs from the apical centrosome, but was essential for the accumulation of non-centrosomal MTs to the sublateral regions. Interestingly, MTCL1 recruited a subpopulation of PAR-1b to the apicobasal MT bundles, and its interaction with PAR-1b was required for MTCL1-dependent development of the apicobasal MT bundles. These results suggest that MTCL1 mediates the epithelial cell-specific reorganization of non-centrosomal MTs through its MT-crosslinking activity, and cooperates with PAR-1b to maintain the correct temporal balance between dynamic and stable MTs within the apicobasal MT bundles.
Type of Medium:
Online Resource
ISSN:
1477-9137
,
0021-9533
Language:
English
Publisher:
The Company of Biologists
Publication Date:
2013
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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