Plant Molecular Biology 53: 297–312, 2003.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
Phragmoplastin dynamics: multiple forms, microtubule association and
their roles in cell plate formation in plants
Zonglie Hong, C. Jane Geisler-Lee, Zhongming Zhang and Desh Pal S. Verma
Department of Molecular Genetics, Department of Plant Biology, and Plant Biotechnology Center, Ohio State Uni-
versity, 240 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210-1002, USA (
author for correspondence;
Received 28 March 2003; accepted in revised form 25 September 2003
Key words: cell division, cytokinesis, dynamin, GTPase, microtubules, vesicle fusion
We have characterized 4 of the 16 members of the family of dynamin-related proteins (DRP) in Arabidopsis.
Three members, DRP1A (previously referred as ADL1), DRP1C and DRP1E, belong to the largest group of
phragmoplastin-like proteins. DRP2A (ADL6) is one of the two members that contain a pleckstrin homology (PH)
domain and a proline-rich (PR) motif, characteristics of animal dynamins. All four proteins interacted in yeast
two-hybrid assays with phragmoplastin, and showed different patterns of localization at the forming cell plate
during cytokinesis. GFP-tagged DRP1A and DRP1C proteins were found to be associated with the cytoskeleton
in G1 phase of the cell cycle. The distribution pattern of DRP1A was sensitive to propyzamid and insensitive to
cytochalasin D, suggesting that DRP1A is associated with microtubules and not actin ﬁlaments. The association
of DRP1A with microtubules was conﬁrmed in vitro by spin-down assays. A GTPase-defective phragmoplastin
acted as a dominant negative mutant, reduced transport of vesicles to the cell plate and formed dense tubule-like
structures in the cell plate. We propose that DRP1 proteins may provide an anchor for Golgi-derived vesicles to
attach to microtubules, which in turn direct the vesicles to the forming cell plate during cytokinesis. Whereas the
DRP1 subfamily members are involved in tubulization of membranes, DRP2 may be involved in endocytosis and
membrane recycling via clathrin-coated vesicles.
Abbreviations: ADL, Arabidopsis dynamin-like protein; C-MT, cortical microtubule; DRP, dynamin-related
protein; GFP, green ﬂuorescent protein; MT, microtubule; PH domain, pleckstrin-homology domain; Phr, phrag-
moplastin; Phr-MT, phragmoplast microtubule; PI, phosphatidylinositol; PI-3P, phosphatidylinositol 3-phosphate;
PRD, proline-rich domain; TVN, tubulo-vesicular network; VTV, vesiculo-tubule vesicle.
Phragmoplastin and ADL1 were the ﬁrst dynamin-
related proteins (DRPs) identiﬁed in plants (Dom-
browski and Raikhel, 1995; Gu and Verma, 1996).
During the past few years, several more DRPs from
plants have been characterized. These include ADL2
(Kang et al., 1998; Kim et al., 2001), ADL2b (Ar-
imura and Tsutsumi, 2002), ADL3 (Mikami et al.,
2000), ADL6 (Jin et al., 2001; Lam et al., 2002; Lee
et al., 2002), and ARC5 (Gao et al., 2003). Arabidop-
sis DRPs have recently been classiﬁed into various
subfamilies based upon their homologies and possible
functions (Hong et al., 2003).
Animal dynamin was originally isolated from
bovine brain extracts as a microtubule-binding protein
(Shpetner and Vallee, 1989), and its GTPase activity
was shown to be activated by microtubules (Shpetner
and Vallee, 1992). It has been suggested that dy-
namin GTPase may be involved in the transport of
Golgi-derived vesicles along the microtubules, from
the minus end to the plus end (Fullerton et al., 1998).
Recently dynamin has also been found to be associ-
ated with actin and shown to play a role in actin-based