Microtubule-dependent microtubule nucleation based on recruitment of γ-tubulin in higher plants

Journal Article · Sun Sep 04 00:00:00 EDT 2005 · Nature Cell Biology

DOI:https://doi.org/10.1038/ncb1306· OSTI ID:2483286

Murata, Takashi ^[1]; Sonobe, Seiji ^[2]; Baskin, Tobias I. ^[3]; Hyodo, Susumu ^[4]; Hasezawa, Seiichiro ^[5]; Nagata, Toshiyuki ^[4]; Horio, Tetsuya ^[6]; Hasebe, Mitsuyasu ^[1]

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1. National Institute for Basic Biology, Okazaki (Japan); The Graduate University for Advanced Studies, Kanagawa (Japan)
2. University of Hyogo (Japan)
3. University of Massachusetts, Amherst, MA (United States)
4. University of Tokyo (Japan)
5. University of Tokyo, Chiba (Japan)
6. University of Tokushima Graduate School (Japan)

Despite the absence of a conspicuous microtubule-organizing centre, microtubules in plant cells at interphase are present in the cell cortex as a well oriented array. A recent report suggests that microtubule nucleation sites for the array are capable of associating with and dissociating from the cortex. Here, we show that nucleation requires extant cortical microtubules, onto which cytosolic γ-tubulin is recruited. In both living cells and the cell-free system, microtubules are nucleated as branches on the extant cortical microtubules. The branch points contain γ-tubulin, which is abundant in the cytoplasm, and microtubule nucleation in the cell-free system is prevented by inhibiting γ-tubulin function with a specific antibody. When isolated plasma membrane with microtubules is exposed to purified neuro-tubulin, no microtubules are nucleated. However, when the membrane is exposed to a cytosolic extract, γ-tubulin binds microtubules on the membrane, and after a subsequent incubation in neuro-tubulin, microtubules are nucleated on the pre-existing microtubules. Furthermore, we propose that a cytoplasmic γ-tubulin complex shuttles between the cytoplasm and the side of a cortical microtubule, and has nucleation activity only when bound to the microtubule.

• Research Organization: University of Massachusetts, Amherst, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: FG02-03ER15421
• OSTI ID: 2483286
• Journal Information: Nature Cell Biology, Journal Name: Nature Cell Biology Journal Issue: 10 Vol. 7; ISSN 1465-7392
• Publisher: Springer Nature
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES