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Full-Text Articles in Medicine and Health Sciences
Multiple Mechanisms Regulate Numa Dynamics At Spindle Poles, Olga Kisurina-Evgenieva, Gary Mack, Quansheng Du, Ian Macara, Alexey Khodjakov, Duane A. Compton
Multiple Mechanisms Regulate Numa Dynamics At Spindle Poles, Olga Kisurina-Evgenieva, Gary Mack, Quansheng Du, Ian Macara, Alexey Khodjakov, Duane A. Compton
Dartmouth Scholarship
The large coiled-coil protein NuMA plays an essential role in organizing microtubule minus ends at spindle poles in vertebrate cells. Here, we use both in vivo and in vitro methods to examine NuMA dynamics at mitotic spindle poles. Using fluorescence recovery after photobleaching, we show that an exogenously expressed green-fluorescent-protein/NuMA fusion undergoes continuous exchange between soluble and spindle-associated pools in living cells. These dynamics require cellular energy and display an average half-time for fluorescence recovery of approximately 3 minutes. To explore how NuMA dynamics at spindle poles is regulated, we exploited the association of NuMA with microtubule asters formed in …
Fibroblast Growth Factor 2 Endocytosis In Endothelial Cells Proceed Via Syndecan-4-Dependent Activation Of Rac1 And A Cdc42-Dependent Macropinocytic Pathway, Eugene Tkachenko, Esther Lutgens, Radu-Virgil Stan, Michael Simons
Fibroblast Growth Factor 2 Endocytosis In Endothelial Cells Proceed Via Syndecan-4-Dependent Activation Of Rac1 And A Cdc42-Dependent Macropinocytic Pathway, Eugene Tkachenko, Esther Lutgens, Radu-Virgil Stan, Michael Simons
Dartmouth Scholarship
Full activity of fibroblast growth factors (FGFs) requires their internalization in addition to the interaction with cell surface receptors. Recent studies have suggested that the transmembrane proteoglycan syndecan-4 functions as a FGF2 receptor. In this study we investigated the molecular basis of syndecan endocytosis and its role in FGF2 internalization in endothelial cells. We found that syndecan-4 uptake, induced either by treatment with FGF2 or by antibody clustering, requires the integrity of plasma membrane lipid rafts for its initiation, occurs in a non-clathrin-, non-dynamin-dependent manner and involves Rac1, which is activated by syndecan-4 clustering. FGF2 was internalized in a complex …
The Gtp-Bound Form Of The Yeast Ran/Tc4 Homologue Blocks Nuclear Protein Import And Appearance Of Poly(A)+ Rna In The Cytoplasm., Gabriel Schlenstedt, Claudio Saavedra, Jonathan D. Loeb, Charles N. Cole, Pamela A. Silver
The Gtp-Bound Form Of The Yeast Ran/Tc4 Homologue Blocks Nuclear Protein Import And Appearance Of Poly(A)+ Rna In The Cytoplasm., Gabriel Schlenstedt, Claudio Saavedra, Jonathan D. Loeb, Charles N. Cole, Pamela A. Silver
Dartmouth Scholarship
Ran/TC4, a Ras-like GTP-binding protein, and its nucleotide exchanger, RCC1, have been implicated in control of protein movement into the nucleus and cytoplasmic accumulation of mRNA. Saccharomyces cerevisiae contains two homologues of the mammalian Ran/TC4, encoded by the GSP1 and GSP2 genes. We have constructed yeast strains that overproduce either wild-type Gsp1 or a form of Gsp1 with glycine-21 converted to valine (Gsp1-G21V), which we show stabilizes the GTP-bound form. Cells producing Gsp1-G21V have defects in localization of nuclear proteins; nuclear proteins accumulate in the cytoplasm following galactose induction of Gsp1-G21V. Similarly, cells producing Gsp1-G21V retain poly(A)+ RNA in their …