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Full-Text Articles in Biology

Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue Mar 1986

Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue

Dartmouth Scholarship

Microtubule proteins isolated from calf brain will undergo gelation-contraction in the presence of ATP. We have now examined this process by video-enhanced contrast microscopy. After ATP addition to steady-state microtubules, slow (1-5 micron/min), linear movements of particles and microtubules toward aggregation centers occur. The resulting structures resemble mitotic spindle asters. During the time when gel contraction occurs, asters move (at 1-5 micron/min) toward other nearby asters. This is accompanied by the apparent shortening of the microtubules running between the asters. This is the first example of isolated microtubules undergoing a process that has similarities to half-spindle shortening during anaphase A. …


Partial Reconstruction Of The Microvillus Core Bundle: Characterization Of Villin As A Ca(++)-Dependent, Actin-Bundling/Depolymerizing Protein, Paul T. Matsudaira, David Burgess Mar 1982

Partial Reconstruction Of The Microvillus Core Bundle: Characterization Of Villin As A Ca(++)-Dependent, Actin-Bundling/Depolymerizing Protein, Paul T. Matsudaira, David Burgess

Dartmouth Scholarship

The brush border, isolated from chicken intestine epithelial cells, contains the 95,000 relative molecular mass (M(r)) polypeptide, villin. This report describes the purification and characterization of villin as a Ca(++)-dependent, actin bundling/depolymerizing protein. Then 100,000 g supernatant from a Ca(++) extract of isolated brush borders is composed of three polypeptides of 95,000 (villin), 68,000 (fimbrin), and 42,000 M(r) (actin). Villin, following purification from this extract by differential ammonium sulfate precipitation and ion-exchange chromatography, was mixed with skeletal muscle F-actin. Electron microscopy of negatively stained preparations of these villin-actin mixtures showed that filament bundles were present. This viscosity, sedimentability, and ultrastructural …