Scanning transmission electron microscopic analysis revealed that the 14S fraction of Tetrahymena dynein was of a mixture of two types of particles in approximately equal proportions. The 14S dynein molecules were roughly ellipsoid in shape with approximate axes of 9.5 and 14.5 nm. About half of the particles had tails 20-24-nm long. By the integration of electron scattering intensities, particles with tails had an average mass of 510 kD with a SD of 90 kD. The globular heads of both types of particles had an average mass of 330 kD with a SD of 60 kD. The mass of the tail structure was about 180 kD. By SDS-PAGE, the 14S dynein consisted of two high molecular mass polypeptides above 300 kD that could be distinguished by immunoblot analysis.
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http://dx.doi.org/10.1083/jcb.106.1.127 | DOI Listing |
FEBS Lett
June 2018
Department of Physics, Oregon State University, Corvallis, OR, USA.
In most eukaryotes, cytoplasmic dynein serves as the primary cytoskeletal motor for minus-end-directed processes along microtubules. However, land plants lack dynein, having instead a large number of kinesin-14s, which suggests that kinesin-14s may have evolved to fill the cellular niche left by dynein. In addition, land plants do not have centrosomes, but contain specialized microtubule-based structures called phragmoplasts that facilitate the formation of new cell walls following cell division.
View Article and Find Full Text PDFNat Commun
March 2018
Department of Physics, Oregon State University, Corvallis, OR, 97331, USA.
In animals and fungi, cytoplasmic dynein is a processive minus-end-directed motor that plays dominant roles in various intracellular processes. In contrast, land plants lack cytoplasmic dynein but contain many minus-end-directed kinesin-14s. No plant kinesin-14 is known to produce processive motility as a homodimer.
View Article and Find Full Text PDFMol Biol Cell
June 2007
Molecular, Cellular, and Developmental Biology Department, University of Colorado at Boulder, Boulder, CO 80309, USA.
Chromosome biorientation, the attachment of sister kinetochores to sister spindle poles, is vitally important for accurate chromosome segregation. We have studied this process by following the congression of pole-proximal kinetochores and their subsequent anaphase segregation in fission yeast cells that carry deletions in any or all of this organism's minus end-directed, microtubule-dependent motors: two related kinesin 14s (Pkl1p and Klp2p) and dynein. None of these deletions abolished biorientation, but fewer chromosomes segregated normally without Pkl1p, and to a lesser degree without dynein, than in wild-type cells.
View Article and Find Full Text PDFEMBO J
October 2006
MCD Biology Department, University of Colorado at Boulder, Boulder, CO 80309, USA.
Prometaphase kinetochores interact with spindle microtubules (MTs) to establish chromosome bi-orientation. Before becoming bi-oriented, chromosomes frequently exhibit poleward movements (P-movements), which are commonly attributed to minus end-directed, MT-dependent motors. In fission yeast there are three such motors: dynein and two kinesin-14s, Pkl1p and Klp2p.
View Article and Find Full Text PDFCell Motil Cytoskeleton
May 2004
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
An important challenge is to understand the functional specialization of dynein heavy chains. The ciliary outer arm dynein from Tetrahymena thermophila is a heterotrimer of three heavy chains, called alpha, beta and gamma. In order to dissect the contributions of the individual heavy chains, we used controlled urea treatment to dissociate Tetrahymena outer arm dynein into a 19S beta/gamma dimer and a 14S alpha heavy chain.
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