Related Experiment Video
Updated: May 9, 2026
08:21
F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
Published on: May 4, 2013
Isolation of mitotic apparatus containing vesicles with calcium sequestration activity
Cell
|February 1, 1980
Summary
This study reveals that isolated mitotic apparatus can sequester calcium within vesicles. This ATP-dependent process involves specific vesicular fractions, crucial for understanding calcium regulation during cell division.
Area of Science:
- Cell Biology
- Biochemistry
Background:
- The role of calcium in cell division is well-established, but the mechanisms of calcium sequestration within the mitotic apparatus remain unclear.
- Previous studies have not identified specific intracellular structures responsible for calcium storage during mitosis.
Purpose of the Study:
- To investigate the presence and function of vesicular calcium sequestration within isolated mitotic apparatus.
- To characterize the molecular mechanisms underlying calcium uptake and retention by these vesicles.
Main Methods:
- Isolation of mitotic apparatus from cells.
- Microscopic examinations (phase-contrast, DIC, polarized light, TEM, SEM).
- Biochemical assays using 45Ca, ATP, ATP analogs, and ionophores; sucrose density gradient centrifugation.
Main Results:
- Isolated mitotic apparatus contain membrane-bound vesicles that retain osmotic activity and cellular components like microtubules and chromatin.
- ATP-dependent sequestration of 45Ca was demonstrated in intact vesicles, with significant enhancement (184%) compared to controls.
- Vesicle disruption with Triton X-100 abolished calcium accumulation, and sucrose gradient analysis identified a specific vesicular fraction responsible for sequestration.
Conclusions:
- The study provides the first evidence of vesicular calcium sequestration in isolated mitotic apparatus.
- This sequestration is an active, ATP-dependent process mediated by specific vesicular components.
- Understanding this mechanism is vital for comprehending calcium's role in cell division regulation.
Related Concept Videos
01:38Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
01:33Overview of Secretory Vesicles
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
01:26Fusion of Secretory Vesicles with the Plasma Membrane
Proteins and neurotransmitters in secretory vesicles can be released from a cell upon vesicle docking, priming, and fusion with the plasma membrane. Vesicles are docked and primed in preparation for the quick exocytosis of their contents in response to a stimulus. The fusion process is mainly carried out by a SNAP Receptor or SNARE complex, consisting of synaptobrevin, syntaxin-1, and SNAP-25.
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
01:15Drugs that Stabilize Microtubules
Microtubules are dynamic structures that undergo cycles of catastrophe and rescue. The microtubules play a central role in cell division by forming the spindle apparatus for segregating the chromosomes. This makes them ideal targets for regulating dividing cells in tumors and malignant cancer cells. Microtubule stabilizing drugs help stabilize the microtubule formation and promote its polymerization. Paclitaxel was the first microtubule stabilizing agent used as anticancer drug in chemotherapy...