Plant Cell Monogr (9)
D.P.S. Verma and Z. Hong: Cell Division Control in Plants
DOI 10.1007/7089_2007_133/Published online: 28 July 2007
©Springer-Verlag Berlin Heidelberg 2007
Molecular Analysis of the Cell Plate Forming Machinery
Zonglie Hong^1 ()·DeshPalS.Verma^2
(^1) Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho,
Moscow, Idaho 83844, USA
[email protected]
(^2) Department of Molecular Genetics and Plant Biotechnology Center,
The Ohio State University, Columbus, Ohio 43210, USA
AbstractThe cell plate is built using Golgi-derived vesicles carrying various proteins,
sugars and lipids, which are required for thede novosynthesis of the cell wall during
cytokinesis. The processes of vesicle fusion, cell plate expansion and maturation are ini-
tiated and controlled by a large number of proteins that serve as structural components,
transporters, enzymes, and regulatory elements. Since the identification of phragmoplas-
tin, the first protein marker of the cytokinetic organelle phragmoplast, a number of cell
plate-associated proteins have been identified and characterized. Some of these proteins
appear to be unique to the process of cell plate formation, while others have functions in
different subcellular locations and are recruited to the forming cell plate transiently dur-
ing cytokinesis. A temporal and spatial orchestration of basic exocytotic and endocytotic
processes culminate in to formation of this unique subcellular compartment. Completion
of this process in a defined time is essential for a proper cell division.
1
Phragmoplastin, the First Protein Marker of the Cell Plate
Phragmoplastin was first cloned from soybean in an attempt to identify pro-
teins required for vacuole biogenesis (Gu and Verma 1996). The cloning was
based on its homology with yeast VPS1, a dynamin-like GTPase required for
the formation of vacuoles (Rothman et al. 1990; Ekena and Stevens 1995).
This protein was found to be associated with the forming cell plate and
phragmoplast-microtubules using its polyclonal antibodies (Fig. 1) and the
GFP tag (Gu and Verma 1996, 1997; Hong et al. 2003b), and was accordingly
named as phragmoplastin. Although the phragmoplast structure was known
for a long time, no specific protein marker for this “organelle” was available at
the time when phragmoplastin was identified. Earlier studies on cell plate for-
mation were based primarily on anatomical observations and histochemical
staining such as aniline blue that stains callose deposited on the forming cell
plate (Gunning and Wick 1985; Mineyuki and Gunning 1990). The event of
callose deposition, however, occurs much later then the initiation of cell plate
by fusion of the Golgi-derived vesicles.
Phragmoplastin is a 68 kD GTPase related to the dynamin family of pro-
teins, but does not contain either thepleckstrinhomology (PH) orproline-