Motor Proteins of Cytoplasmic Microtubules

Vallee, Richard B.; Shpetner, Howard S.

doi:10.1146/annurev.bi.59.070190.004401

Cited by 198 publications

(78 citation statements)

References 55 publications

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“…Dynamin is a 100 M r GTP-driven mechanochemical enzyme related to mammalian mx-proteins, the yeast vps 1 gene product and Drosophila melanogaster shibire [114]. First identified as a microtubule-associated motor proteinlike activity [115], dynamin is implicated in the recapture of intact secretory vesicles in PC12 cells [105,116]. Dynamin-1, the principal isoform in neuronal and neuroendocrine cells, possesses GTPase, pleckstrin homology and C-terminal proline-rich domains, and is proposed to act either as a mechanochemical enzyme that cleaves the neck of an endocytosing vesicle ("pinchase") [117], or as a molecular spring ("poppase") that extends and eventually ruptures the tubule linking the vesicle and donor membrane [118].…”

Section: The Fate Of the Transiently Fused Vesicle: Nanomechanics Of mentioning

confidence: 99%

Visualising insulin secretion. The Minkowski Lecture 2004

Rutter

2004

Diabetologia

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Insulin secretion from pancreatic islet beta cells is a tightly regulated process, under the close control of blood glucose concentrations, neural inputs and circulating hormones. Defects in glucose-triggered insulin secretion, possibly exacerbated by a decrease in beta cell mass, are ultimately responsible for the development of type 2 diabetes. A full understanding of the mechanisms by which glucose and other nutrients trigger insulin secretion will probably be essential to allow for the development of new therapies of type 2 diabetes and for the derivation of "artificial" beta cells from embryonic stem cells as a treatment for type 1 diabetes. I focus here on recent developments in our understanding of beta cell glucose sensing, achieved in part through the development of recombinant targeted probes (luciferase, green fluorescent protein) that allow islet beta cell metabolism and Ca 2+ handling to be imaged in situ in the intact islet with single cell resolution. Combined with classical biochemistry, these techniques show that the beta cell is uniquely poised, thanks to the expression of low levels of lactate dehydrogenase and plasma membrane lactate/monocarboxylate transporters, to channel glucose carbons towards oxidative metabolism, ATP synthesis and inhibition of AMP-activated protein kinase, a newly defined regulator of insulin release. I also discuss the molecular basis of the recruitment of secretory vesicles to the cell surface, analysed by the use of new imaging techniques including total internal reflection of fluorescence, as well as the "nanomechanics" of the exocytotic event itself.

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Section: The Fate Of the Transiently Fused Vesicle: Nanomechanics Of mentioning

confidence: 99%

Visualising insulin secretion. The Minkowski Lecture 2004

Rutter

2004

Diabetologia

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“…The force generating mechanism of this step may depend on microtubule-associated motor molecules such as kinesin that generate plus-directed movement between astral microtubules and the cortex. Alternatively, force may be generated by microtubule motors that promote sliding between two populations of microtubules (see Vallee and Shpetner, 1990), some of which would be part of the sperm aster while others would be anchored to the cortex. During the second step, the sperm aster moves at ~10/~m/min to its final location toward the center of the egg, whereas the myoplasm and the ER domain move at ,,026 t~m/min in the same direction.…”

Section: Accumulated Er Is Relocalized During the Second Phase Of Oopmentioning

confidence: 99%

Polarity and reorganization of the endoplasmic reticulum during fertilization and ooplasmic segregation in the ascidian egg.

Speksnijder

Terasaki

Hage

et al. 1993

The Journal of Cell Biology

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Abstract. During the first cell cycle of the ascidian egg, two phases of ooplasmic segregation create distinct cytoplasmic domains that are crucial for later development. We recently defined a domain enriched in ER in the vegetal region of Phaltusia mammillata eggs. To explore the possible physiological and developmental function of this ER domain, we here investigate its organization and fate by labeling the ER network in vivo with DiICl6(3), and observing its distribution before and after fertilization in the living egg. In unfertilized eggs, the ER-rich vegetal cortex is overlaid by the ER-poor but mitochondria-rich subcortical myoplasm. Fertilization results in striking rearrangements of the ER network. First, ER accumulates at the vegetal-contraction pole as a thick layer between the plasma membrane and the myoplasm. This accompanies the relocation of the myoplasm toward that region during the first phase of ooplasmic segregation. In other parts of the cytoplasm, ER becomes progressively redistributed into ER-rich and ER-poor microdomains. As the sperm aster grows, ER accumulates in its centrosomal area and along its astral rays. During the second phase of ooplasmic segregation, which takes place once meiosis is completed, the concentrated ER domain at the vegetal-contraction pole moves with the sperm aster and the bulk of the myoplasm toward the future posterior side of the embryo. These results show that after fertilization, ER first accumulates in the vegetal area from which repetitive calcium waves are known to originate (Speksnijder, J. E. 1992. . This ER domain subsequently colocalizes with the myoplasm to the presumptive primary muscle cell region.T nE ER is a key cellular organelle involved in the synthesis of membrane lipids and proteins, secretion, and calcium homeostasis. Morphologically, it is organized as a continuous and extensive network of tubules and cisternae with typical three-way junctions. A number of recent studies have revealed that it is a highly dynamic structure which interacts with a variety of cellular constituents, including microtubules and actin filaments (Terasaki et al.,

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“…pothesis was confirmed after the development of in vitro microtubule motility assays (Vale et al, 1985;Paschal et al, 1987). These assays have permitted the identification of both kinesin and dynein motors in the soluble extracts of cells that contain no ciliary or flagellar axonemes (reviewed in Vallee and Shpetner, 1990;Bloom, 1992;Skoufias and Scholey, 1993).…”

Section: Introductionmentioning

confidence: 99%

A family of dynein genes in Drosophila melanogaster.

Rasmusson

Serr

Gepner

et al. 1994

MBoC

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We report the identification and initial characterization of seven Drosophila dynein heavy chain genes. Each gene is single copy and maps to a unique genomic location. Sequence analysis of partial clones reveals that each encodes a highly conserved portion of the putative dynein hydrolytic ATP-binding site in dyneins that includes a consensus phosphate-binding (P-loop) motif. One of the clones is derived from a Drosophila cytoplasmic dynein heavy chain gene, Dhc64C, that shows extensive amino acid identity to cytoplasmic dynein isoforms from other organisms. Two other Drosophila dynein clones are 85 and 90% identical at the amino acid level to the corresponding region of the beta heavy chain of sea urchin axonemal dynein. Probes for all seven of the dynein-related sequences hybridize to transcripts that are of the appropriate size, approximately 14 kilobases, to encode the characteristic high molecular weight dynein heavy chain polypeptides. The Dhc64C transcript is readily detected in RNA from ovaries, embryos, and testes. Transcripts from five of the six remaining genes are also detected in much lesser amounts in tissues other than testes. All but one of the dynein transcripts are expressed at comparable levels in testes suggesting their participation in flagellar axoneme assembly and motility.

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Motor Proteins of Cytoplasmic Microtubules

Cited by 198 publications

References 55 publications

Visualising insulin secretion. The Minkowski Lecture 2004

Visualising insulin secretion. The Minkowski Lecture 2004

Polarity and reorganization of the endoplasmic reticulum during fertilization and ooplasmic segregation in the ascidian egg.

A family of dynein genes in Drosophila melanogaster.

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