Phragmoplast

The phragmoplast can only be observed in Phragmoplastophyta, a clade that includes the Coleochaetophyceae, Zygnematophyceae, Mesotaeniaceae, and Embryophyta (land plants).

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

The formation of the cell plate depends on localized secretory vesicle fusion to deliver membrane and cell-wall components.

[4] Most research into phragmoplast MAPs have been focused on the midline because it is, first, where most of the membrane fusion takes place and, second, where the two sets of anti-parallel MTs are held together.

[17] The essential mechanism of MAPK cascade for phragmoplast expansion is suppressed by cyclin dependent kinase (CDK) activity before telophase.

[22] RUNKEL, which is a HEAT repeat-containing MAP, also accumulates at the midline and cytokinesis is aberrant in lines with the loss-of-function mutations in this protein.

[23][24] Another midline-localized protein, “two-in-on” (TIO), is a putative kinase and is also required for cytokinesis as shown by defects in a mutant.

Phragmoplast and cell plate formation in a plant cell during cytokinesis. Left side: Phragmoplast forms and cell plate starts to assemble in the center of the cell. Towards the right: Phragmoplast enlarges in a donut-shape towards the outside of the cell, leaving behind mature cell plate in the center. The cell plate will transform into the new cell wall once cytokinesis is complete.