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The Centrosome Keeps Nucleating Microtubules but Looses the Ability to Anchor Them after the Inhibition of Dynein-Dynactin Complex

O. N. Zhapparova1,2, A. V. Burakov3*, and E. S. Nadezhdina1,3

1Institute of Protein Research, Russian Academy of Sciences, ul. Institutskaya 4, 142290 Pushchino, Moscow Region, Russia; fax: (495) 632-7871; E-mail: elena.nadezhdina@gmail.com

2Biological Faculty, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-4309; E-mail: olga.zhapparova@gmail.com

3Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-3181; E-mail: antburakov@yandex.ru

* To whom correspondence should be addressed.

Received April 18, 2007; Revision received June 21, 2007
We inhibited dynein in cells either by the expression of coiled coil-1 (CC1) fragment of dynactin p150Glued subunit or by the microinjection of CC1 protein synthesized in Escherichia coli. CC1 impeded the aggregation of pigment granules in fish melanophores and caused the dispersion of Golgi in Vero and HeLa cells. These data demonstrated the inhibiting effect of CC1 on dynein. In cultured cells, CC1 expression caused the disruption of microtubule array, while the nucleation of new microtubules remained unaltered. This was proved both with in vivo microtubule recovery after nocodazole treatment and with in vitro microtubule polymerization on centrosomes, when the number of nucleated microtubules marginally reduced after the incubation with CC1. Moreover, the inhibiting anti-dynein 74.1 antibodies caused the same effect. Thus we have shown that though dynein is not important for microtubule nucleation, it is essential for the radial organization of microtubules presumably being involved in microtubule anchoring on the centrosome.
KEY WORDS: dynein, dynactin, microtubules, centrosome, p150Glued, microinjections, melanophores

DOI: 10.1134/S0006297907110090