phragmoplast

The phragmoplast is a plant cell specific structure that forms during late cytokinesis.

The cell plate initially forms as a disc between the two halves of the phragmoplast structure.

Once the cell plate reaches and fuses with the plasma membrane the phragmoplast disappears.

This process is facilitated by a phragmoplast, a microtubule array unique to plant cell mitosis.

Actin filaments are also possibly involved in guiding the phragmoplast to the site of the former preprophase band location at the parent cell wall.

If a phragmosome was present in the cell, the phragmoplast and cell plate will grow through the space occupied by the phragmosome.

In land plant cells, vesicles derived from the Golgi apparatus move to the middle of the cell along a microtubule scaffold called the phragmoplast.

The microtubules and actin filaments within the phragmoplast serve to guide vesicles with cell wall material to the growing cell plate.

In plants this structure coalesces into a cell plate at the center of the phragmoplast and develops into a cell wall, separating the two nuclei.

Cell division is also characterized by the development of a phragmoplast for the construction of a cell plate in the late stages of cytokinesis.

As the cell plate matures in the central part of the cell, the phragmoplast disassembles in this region and new elements are added on its outside.

The phragmoplast is a microtubule structure typical for higher plants, whereas some green algae use a phycoplast microtubule array during cytokinesis.

Formation and growth of the cell plate is dependent upon the phragmoplast, which is required for proper targeting of Golgi-derived vesicles to the cell plate.

This process leads to a steady expansion of the phragmoplast and, concomitantly, to a continuous retargeting of Golgi-derived vesicles to the growing edge of the cell plate.

The phragmoplast is assembled from the remnants of the mitotic spindle, and serves as a track for the trafficking of vesicles to the phragmoplast midzone.

The phragmoplast can only be observed in Embryophytes, that is the bryophytes and vascular plants and a few advanced green algae, specifically Coleochaete in the Division Charophyta.

In plant cells, Golgi vesicle secretions form a cell plate or septum on the equatorial plane of the cell wall by the action of microtubules of the phragmoplast.

In these algae, the microtubules of the telophase spindle give rise to the phragmoplast and are oriented perpendicular to the plane of cell division and the forming cell plate.

On a microscopic level, the cells of embryophytes are broadly similar to those of green algae, but differ in that in cell division the daughter nuclei are separated by a phragmoplast.

While new cell plate material is added to the edges of the growing plate, the phragmoplast microtubules disappear in the center and regenerate at the edges of the growing cell plate.

Myosin VIII is a plant-specific myosin linked to cell division; specifically, it is involved in regulating the flow of cytoplasm between cells and in the localization of vesicles to the phragmoplast.

The cleavage furrow in animal cells and the phragmoplast in plant cells are complex structures made up of microtubules and microfilaments that aide in the final separation of the cells into two identical daughter cells.

For example, during cell division in plants several plant-specific MT arrays such as the preprophase band and the phragmoplast are formed that are important in determining the future location of the cell wall and cell wall formation, respectively.

Three Arabidopsis kinesins, Kat A, KCBP and PAKRP, have been shown to be associated with the phragmoplast [ 39, 48, 69] and so are expected to be necessary in some way for cytokinesis.

A few of the C-terminal Arabidopsis kinesins (e.g., KatA, KCBP) have been localized to mitotic MT arrays (spindle, spindle poles, and phragmoplast) [ 33, 48], suggesting a role for these kinesins in cell division.