The rates of change at either end are not balanced — one end grows more rapidly and is called the plus end, whereas the other end is known as the minus end. In cells, the minus ends of microtubules are anchored in structures called microtubule organizing centers (MTOCs).
The minus ends of each microtubule begin at the centrosome, while the plus ends radiate out in all directions. Thus the centrosome is also important in maintaining the polarity of microtubules during mitosis.
the centrosomeIntracellular organization of microtubules. The minus ends of microtubules are anchored in the centrosome. In interphase cells, the centrosome is located near the nucleus and microtubules extend outward to the cell periphery.
Microtubules are cytoskeletal filaments essential for numerous aspects of cell physiology. They are polarized polymeric tubes with a fast growing plus end and a slow growing minus end.
Organization of microtubules by oligomeric motors During cell division, the minus ends of spindle microtubules are tightly focused at the spindle poles. This ensures that segregating chromosomes move to a single location, where the nucleus of the daughter cell will eventually form.
Why are the ends of microfilaments and microtubules called "plus ends" and "minus ends"? -Because the actin and tubulin monomers that make up microfilaments and microtubules have evolved more rapidly than most other proteins.
Cofilin functions by binding to ADP-actin on the negative end of the filament, destabilizing it, and inducing depolymerization. Profilin induces ATP binding to G-actin so that it can be incorporated onto the positive end of the filament.
minus endsThe minus ends of spindle microtubules depolymerize at the poles, while their plus ends undergo net polymerization; as a result, spindle microtubules translocate towards the poles, a process termed poleward microtubule flux [22].
A centriole is a small set of microtubules arranged in a specific way. There are nine groups of microtubules. When two centrioles are found next to each other, they are usually at right angles. The centrioles are found in pairs and move towards the poles (opposite ends) of the nucleus when it is time for cell division.
Catastrophe—the switch from growing to shrinking—occurs when a microtubule loses its stabilizing GTP cap. Recent evidence indicates that the nucleotide on the microtubule end controls how tightly an incoming subunit will be bound (trans-acting GTP), but most current models do not incorporate this information.
Abstract. Microtubules are cytoskeletal polymers whose function depends on their property to switch between states of growth and shrinkage. Growing microtubules are thought to be stabilized by a GTP cap at their ends.
The cap is formed through a 5'-5' linkage between the two substrates such that the GTP molecule is oriented in the opposite direction as the other nucleotides in the RNA transcript chain. Once in place, the cap plays a role in the ribosomal recognition of messenger RNA during translation into a protein.