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. Author manuscript; available in PMC: 2013 Jun 10.
Published in final edited form as: Trends Cell Biol. 2005 Aug;15(8):404–413. doi: 10.1016/j.tcb.2005.06.003

Figure 2.

Figure 2

Models for assembly of the midbody and phragmoplast. (a) Model depicting midbody organization. Overlapping microtubule plus-ends are embedded within the midbody matrix. The midbody microtubules are stabilized and crosslinked by several kinesins, microtubule-associated proteins (MAPs), kinases and other proteins, such as MKLP1/ZEN-4/PAV, MgcRACGAP/CYK-4, PRC1/SPD-1/FEO/Ase1p, chTOG/ZYG-9/Msps, TACC/TAC-1, CLIP-170, EB1, KLP61F/BimC, and the chromosomal passengers Aurora B/AIR-2, Survivin/BIR-1, INCENP/ICP-1, -2 and Borealin/CSC-1. PRC1 is possibly transported by KIF4 along the midzone microtubules (MTs). It is possible that KIF4 also transports Golgi-derived vesicles along midbody MTs where they fuse with the ingressing furrow. ZEN-4 and PRC1 are phosphorylated by Cdk1. Golgi assembly occurs when Cdk1 activity is low in telophase. Golgi stack assembly is also promoted by the degradation of Polo kinase and MEK1 in telophase (U: ubiquitin moiety). NIR2, a Golgi-associated protein, is found more prominently on the cleavage furrow as well as the spindle midzone in telophase to cytokinesis in a complex with Polo kinase. Membrane fusion occurs at the tips and along the ingressing furrow and involves a variety of proteins such as the exocyst complex, SNAREs, dynamin/DYN-1 and their interactors. Note: to simplify the figure, we have omitted several homologs/orthologs of several proteins. (b) Model depicting phragmoplast organization in plant cells. Microtubule plus-ends enclosed inside the cell-plate assembly matrix (CPAM) are stabilized and crosslinked by several MAPs, such as MAP55-1, MAP65-3, MOR1/GEM1, and by kinesin motor proteins. Golgi-derived vesicles are transported to the division plane along MTs by a kinesin motor protein, where they fuse with others while enclosed by the CPAM. Membrane fusion at the cell plate involves a variety of proteins such as tethering factors, SNAREs and their interactors. Formation of tubular domains in the developing cell plate appears to be mediated by DRP1A.