In this case, heterozygous mutants may not exhibit a 50% defective seed phenotype observed in other classes of female gametophyte mutants (Drews et al., 1998) because of the presence of a maternally inherited pool of ADL1Ap. did not display any defects in cytokinesis, and growth of the mutant seedlings could be rescued in tissue culture by the addition of sucrose. Although these sucrose-rescued plants displayed normal vegetative growth and flowered, they set very few seeds. Thus, ADL1Ap is critical for several stages of plant development, including embryogenesis, seedling development, and reproduction. We discuss the putative role of ADL1Ap in vesicular trafficking, cytokinesis, and other aspects of plant growth. Dynamin and dynamin-related proteins are a family of structurally related, but functionally diverse high gene product, have been demonstrated to function in clathrin-dependent endocytosis, trans-Golgi network (TGN) vesicle budding (Jones et al., 1998), and in the internalization of caveloae (Henley et al., 1998; Oh et al., 1998). Considerable biochemical, genetic, and morphological evidence (van der Bliek and Meyerowitz, 1991; Hinshaw and Schmid, 1995; Takei et al., 1995) suggests that dynamin oligomerizes into multimeric rings around the neck of invaginating clathrin-coated vesicles and functions as a mechanoenzyme, releasing the nascent vesicles from the plasma membrane upon GTP hydrolysis. Dynamin is also thought to function as a regulatory molecule (Sever et al., 1999), recruiting various binding partners, including other components of the endocytic machinery, lipids, signaling molecules, and cytoskeletal proteins through its many domains (McNiven et al., 2000a). In addition to its role Punicalin in vesicular trafficking, dynamin function has also been linked to actin cytoskeleton dynamics (McNiven et al., 2000b; Ochoa et al., 2000) and signal transduction (Fish et al., 2000). Dynamin-like Punicalin proteins, which generally lack the PH and Pro-rich domains found in dynamin, have been identified in a Punicalin variety of organisms, including yeast, mammals, and plants. Many of these proteins also carry out processes related to membrane dynamics and vesicular trafficking. The yeast dynamin-like protein Vps1p functions in vesicular trafficking between the TGN and endosomes. However, unlike dynamin, it does not play a role in endocytosis (Rothman Punicalin et al., 1990; Wilsbach and Payne, 1993; Nothwehr et al., 1995). Another yeast dynamin-related protein, Dnm1p, controls mitochondrial morphology by regulating the fission of outer mitochondrial membrane tubules (Bleazard et al., 1999; Sesaki and Jensen, 1999). In plants, three dynamin-related protein subfamilies have been identified. One family consists of the soybean and Arabidopsis 68-kD dynamin-like proteins, phragmoplastin and ADL1p, respectively, and another is definitely defined from the 84-kD dynamin-like protein, ADL2p. ADL2p consists of a chloroplast transit sequence and is localized to plastids (Kang Shin et al., 1998), suggesting that ADL2p may play a role in chloroplast/plastid biogenesis and maintenance. A third subfamily consists of the gene product. Similar to the prototypical dynamins, encodes a large 100-kD GTPase-containing a PH website (Mikami et al., 2000); however, its function has not been defined. Dynamin-related proteins are thought to play a major part in flower cell division since the construction of the cytokinetic organelle, known as Rabbit polyclonal to TP53BP1 the cell plate, is definitely highly dependent upon the formation, focusing on, and fusion of secretory vesicles transporting membrane and cell wall material (for review, observe (Staehelin and Hepler, 1996; Verma and Gu, 1996). Consistent with this idea is the recent observation that phragmoplastin is definitely associated with the cell plate in dividing soybean and tobacco cells (Gu and Verma, 1996, 1997). There is, however, conflicting data concerning the localization of the ADL1 protein. One group (Lauber Punicalin et al., 1997) localized ADL1p to the cell plate in embryonic cells, whereas another (Park et al., 1998) offers suggested that ADL1p is definitely associated with chloroplasts and is required for thylakoid membrane biogenesis. It interesting that although these two studies reached different conclusions, they both used the same ADL1p antibody preparation generated against.