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Atomic force microscopy reveal pit-like structures typically containing three or four, approximately 150 nm in diameter depressions at the apical plasma membrane in live pancreatic acinar cells. Stimulation of secretion causes these depressions to dilate and return to their resting size following completion of the process. Exposure of acinar cells to(More)
Fusion pores or porosomes are basket-like structures at the cell plasma membrane, at the base of which, membrane-bound secretory vesicles dock and fuse to release vesicular contents. Earlier studies using atomic force microscopy (AFM) demonstrated the presence of fusion pores at the cell plasma membrane in a number of live secretory cells, revealing their(More)
The swelling of secretory vesicles has been implicated in exocytosis, but the underlying mechanism of vesicle swelling remains largely unknown. Zymogen granules (ZGs), the membrane-bound secretory vesicles in exocrine pancreas, swell in response to GTP mediated by a G(alpha)i3 protein. Evidence is presented here that the water channel aquaporin-1 (AQP1) is(More)
Earlier studies using atomic force microscopy (AFM) demonstrated the presence of fusion pores at the cell plasma membrane in a number of live secretory cells, revealing their morphology and dynamics at nm resolution and in real time. Fusion pores were stable structures at the cell plasma membrane where secretory vesicles dock and fuse to release vesicular(More)
A model of the structure of vertebrate Z-lines and Z-line analogs is introduced and supported by evidence from electron microscope studies of wide Z-lines (rat and feline soleus, and feline and canine cardiac muscles), narrow Z-lines (guppy, newt and frog skeletal muscles), and Z-rods (from a patient with nemaline myopathy and from cardiac muscles of aged(More)
Vinculin, isolated from turkey gizzard smooth muscle, was purified by chromatography on CM-cellulose after isolation from a DEAE-cellulose column. Two-dimensional gel electrophoretic analysis of crude muscle fractions demonstrated that: 1) much of the approximately 130,000-dalton protein present in smooth muscle did not co-isoelectrically focus with the(More)
Electrical stimulation (ES) of bovine carcasses is usually done to increase tenderness and has been hypothesized to increase the activity of proteolytic enzymes that may degrade structural proteins in muscle cells and cause fractures and breaks in muscle fibers, thus enhancing meat tenderness. Our objective was to compare postmortem (PM) changes in the(More)
Highly purified alpha-actinin can be made by using the low ionic strength extraction procedure previously described (Arakawa N., Robson, R. M., and Goll, D. E. (1970) Biochim. Biophys. Acta 200, 284-295) and then subjecting the crude alpha-actinin fraction obtained with this extraction procedure to successive chromatography on DEAE-cellulose and(More)
Rat soleus muscle Z-lines and Z-line anomalies induced by neostigmine methyl sulfate (NMS) and cat soleus muscle Z-lines and Z-line anomalies induced by tenotomy were examined by electron microscopy before and after dissection of muscle fibers with Ca2+-activated neutral protease (CAF) to elucidate structural properties of Z-lines and related Z-line-type(More)