Golgi as an MTOC: making microtubules for its own good

Zhu, Xiaodong; Kaverina, Irina

doi:10.1007/s00418-013-1119-4

Cited by 94 publications

(108 citation statements)

References 44 publications

(76 reference statements)

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“…Arrays of microtubules still formed in the absence of functional CAMSAP3, however. Growth of these microtubules is likely regulated by centrosomes or by other organelles known to nucleate or anchor microtubules (26)(27)(28). In support of this idea, we detected radial emanation of EB3 comets from various places in CAMSAP3-depleted cells.…”

Section: Discussionsupporting

confidence: 81%

CAMSAP3 orients the apical-to-basal polarity of microtubule arrays in epithelial cells

Toya¹,

Kobayashi²,

Kawasaki³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

129

171

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Polarized epithelial cells exhibit a characteristic array of microtubules that are oriented along the apicobasal axis of the cells. The minus-ends of these microtubules face apically, and the plus-ends face toward the basal side. The mechanisms underlying this epithelial-specific microtubule assembly remain unresolved, however. Here, using mouse intestinal cells and human Caco-2 cells, we show that the microtubule minus-end binding protein CAMSAP3 (calmodulin-regulated–spectrin-associated protein 3) plays a pivotal role in orienting the apical-to-basal polarity of microtubules in epithelial cells. In these cells, CAMSAP3 accumulated at the apical cortices, and tethered the longitudinal microtubules to these sites. Camsap3 mutation or depletion resulted in a random orientation of these microtubules; concomitantly, the stereotypic positioning of the nucleus and Golgi apparatus was perturbed. In contrast, the integrity of the plasma membrane was hardly affected, although its structural stability was decreased. Further analysis revealed that the CC1 domain of CAMSAP3 is crucial for its apical localization, and that forced mislocalization of CAMSAP3 disturbs the epithelial architecture. These findings demonstrate that apically localized CAMSAP3 determines the proper orientation of microtubules, and in turn that of organelles, in mature mammalian epithelial cells.

show abstract

Section: Discussionsupporting

confidence: 81%

CAMSAP3 orients the apical-to-basal polarity of microtubule arrays in epithelial cells

Toya¹,

Kobayashi²,

Kawasaki³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

129

171

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

“…However, the specific mechanisms by which these proteins promote MT nucleation have not been completely clarified 4 . As enrichment of g-TuRC on the Golgi membrane compared with the surrounding cytoplasm has not been clearly detected, a 'selective stabilization model' has been proposed, in which the Golgi membranes provide the field where unstable MT seeds nucleated from the cytoplasmic g-TuRC are stabilized for MT elongation 4 . Although a previous study has speculated that the MT plus-end tracking proteins, CLASPs, perform this function by coating the MT seeds 8 , the present study provides an additional and strong candidate for this role, MTCL1, which interacts with the lateral sides of MTs and stabilizes them (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…However, many differentiated cells such as polarized epithelial cells and neurons have been shown to develop cell-type-specific arrays of MTs that are not anchored to the centrosome 2,3 . Furthermore, recent studies have revealed that, even in less differentiated cells, a subset of MTs is nucleated not from the centrosome, but from the Golgi membrane [4][5][6] . To date, two groups have independently reported the involvement of two different molecular machineries in this novel nucleation process of MTs.…”

mentioning

confidence: 99%

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MTCL1 crosslinks and stabilizes non-centrosomal microtubules on the Golgi membrane

et al. 2014

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Recent studies have revealed the presence of a microtubule subpopulation called Golgi-derived microtubules that support Golgi ribbon formation, which is required for maintaining polarized cell migration. CLASPs and AKAP450/CG-NAP are involved in their formation, but the underlying molecular mechanisms remain unclear. Here, we find that the microtubule-crosslinking protein, MTCL1, is recruited to the Golgi membranes through interactions with CLASPs and AKAP450/CG-NAP, and promotes microtubule growth from the Golgi membrane. Correspondingly, MTCL1 knockdown specifically impairs the formation of the stable perinuclear microtubule network to which the Golgi ribbon tethers and extends. Rescue experiments demonstrate that besides its crosslinking activity mediated by the N-terminal microtubule-binding region, the C-terminal microtubule-binding region plays essential roles in these MTCL1 functions through a novel microtubule-stabilizing activity. These results suggest that MTCL1 cooperates with CLASPs and AKAP450/CG-NAP in the formation of the Golgi-derived microtubules, and mediates their development into a stable microtubule network.

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“…Lecture sessions and poster presentations are dedicated to key topics of present-day Golgi apparatus research: ''The complexity of Golgi trafficking routes in secretion and endocytosis'', ''Protein dynamics, sorting and recycling'', ''Models for antero-and retrograde transport across the stacks of cisternae'', ''Regulation of the Golgi apparatus architecture'', ''Signalling circuits'', ''Mechanisms of Golgi cisternal stacking'', ''Golgi structure-function relationships'', ''Dynamics at the ER-Golgi-interface and the trans Golgi network'', ''Molecular machineries and formation of transport carriers'', ''Golgi apparatus and cytoskeleton'', ''Golgi-derived microtubules'', ''The role of the Golgi apparatus in cell polarity and directional migration'', ''Unconventional transport'', ''Golgi biogenesis'', ''The Golgi apparatus in mitosis and cell division'', ''Golgi organization in response to physiologic and pathologic cellular changes'', ''Golgi dissociation and reorganization, disassembly, reassembly and new formation'', ''The Golgi apparatus in plants, algae and yeast'', ''New technical approaches and novel microscopic methods'' (Boncompain and Perez 2013;Chia et al 2013;Day et al 2013;Egea et al 2013;Machamer 2013;Martínez-Alonso et al 2013;Polishchuk and Lutsenko 2013;Sandvig et al 2013;Tillmann et al 2013;Uemura and Nakano 2013;Warren 2013;Willett et al 2013;Zhu and Kaverina 2013).…”

mentioning

confidence: 99%