Diversity of plant actins

Meagher, Richard B.; McLean, Barbara

doi:10.1002/cm.970160303

Cited by 36 publications

(22 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our understanding of how the plant actin cytoskeleton is regulated has been greatly enhanced in recent years by the identification of genes and proteins for actin and several actin binding proteins (ABPs; reviewed in Meagher and McLean, 1990;McCurdy and Williamson, 1991 ;Meagher, 1991 ;Staiger et al, 1997). The unique constellation of ABPs in each cell probably confers both functional and organizational properties on the cytoskeleton and allows for rapid responses to intracellular and environmental stimuli.…”

Section: Introductionmentioning

confidence: 99%

“…For example, yeast actin and RSMA share 87% amino acid sequence identity, yet their polymerization properties and interaction with yeast profilin differ substantially (Nefsky and Bretscher, 1992;Kim et al, 1996). Plants contain multigene families for diverse actins that share 83 to 89% amino acid sequence identity with other eukaryotic actins (Meagher and McLean, 1990;Meagher, 1991;Meagher and Williamson, 1994). The multigene families for profilin and the actin depolymerizing factor show even less conservation; 25 to 40% identity with eukaryotic counterparts is typical .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Actin Purified from Maize Pollen Functions in Living Plant Cells.

et al. 1997

View full text Add to dashboard Cite

A vast array of actin binding proteins (ABPs), together with intracellular signaling molecules, modulates the spatiotemporal distribution of actin filaments in eukaryotic cells. To investigate the complex regulation of actin organization in plant cells, we designed experiments to reconstitute actin-ABP interactions in vitro with purified components. Because vertebrate skeletal a-actin has distinct and unpredictable binding affinity for nonvertebrate ABPs, it is essential that these in vitro studies be performed with purified plant actin. Here, we report the development of a new method for isolating functional actin from maize pollen. The addition of large amounts of recombinant profilin to pollen extracts facilitated the depolymerization of actin filaments and the formation of a profilin-actin complex. The profilin-actin complex was then isolated by affinity chromatography on poly-L-proline-Sepharose, and actin was selectively eluted with a salt wash. Pollen actin was further purified by one cycle of polymerization and depolymerization. The recovery of functional actin by this rapid and convenient procedure was substantial; the average yield was 6 mg of actin from 10 g of pollen. We undertook an initial physicochemical characterization of this native pollen actin. Under physiological conditions, pollen actin polymerized with kinetics similar in quality to those for vertebrate a-actin and had a critical concentration for assembly of 0.6 pM. Moreover, pollen actin interacted specifically and in a characteristic fashion with several ABPs. Tradescantia cells were microinjected and used as an experimental system to study the behavior of pollen actin in vivo. We demonstrated that purified pollen actin ameliorated the effects of injecting excess profilin into live stamen hair cells.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Actin Purified from Maize Pollen Functions in Living Plant Cells.

et al. 1997

View full text Add to dashboard Cite

show abstract

“…The presence of actin and myosin in higher plants has been identified in Amaryllis, Haemanthus, tomato, conifer root, pollen of Luffa, pea tendrils, and pollen tube of lily (3,5,13,17,20,21,23) by biochemical and immunological methods. But the concentrations of actin in plant are lower than they are in animal cytoplasmic tissues (14). So the biochemical and physiological studies of plant actomyosin are limited, unlike the cases in other nonmuscle cells such as slime molds and Acanthamoeba castellanii.…”

Section: Maize Pollenmentioning

confidence: 99%

“…It has been reported that there are some variations in amino acid composition and sequence of actin among the three kinds of organisms, i.e. plants, animals, and protists (14). The circular dichroism of muscle actin had been determined by Murphy (15).…”

Section: Amino Acid Compositionmentioning

confidence: 99%

See 1 more Smart Citation

Purification and Characterization of Actin from Maize Pollen

Xiong¹,

Yen²

1992

Plant Physiol.

View full text Add to dashboard Cite

Pollen is an excellent source of actin for biochemical and physiological studies of the actomyosin system in higher plants. We have developed an efficient method to prepare relatively high levels of actin from the pollen of maize (Zea mays L.). The procedures of purification include acetone powder preparation, saturated ammonium sulfate fractionation, diethylaminoethyl-cellulose chromatography, a cycle of polymerization-depolymerization, and Sephacryl S-200 gel filtration. The average yield of actin is 19 milligrams per 100 grams of pollen grains extracted. This is comparable with those of Acanthamoeba castellanii and human platelets. The purified pollen actin is electrophoretically homogeneous and its molecular mass is 42 kilodaltons. The amino acid composition and circular dichroism spectrum of pollen actin are identical to those of muscle actin. The actin purified from pollen is able to polymerize to F-actin. The pollen F-actin activated the activity of the muscle myosin ATPase sevenfold. amino acid composition, circular dichroism spectrum, and activation of myosin ATPase activities. MATERIALS AND METHODS ChemicalsDEAE-cellulose and Sephacryl S-200 were obtained from Pharmacia. ATP-Na2 salt, imidazole, SDS, acrylamide, bismethylene-acrylamide, Tris, and monoclonal antibodies against smooth-muscle a-actin were from Sigma. All other reagents used were of analytical grade. Maize PollenMaize (Zea mays L.) plants were grown in the Experimental Station of Beijing Agricultural University in Beijing.The cultivar was Nongda No. 14. Pollen were collected in the middle of July when the plants were in pollination stage. About 1 kg fresh weight of maize pollen was collected and stored in a desiccator placed in a freezer (-700C) for use. It has been well established that the actomyosin system is universally distributed in higher plants (9). The actomyosin system is an important component of cytoskeleton, which plays a pivotal role in the maintenance of cell shape, cell motility, mitosis, and cytokinesis. The presence of actin and myosin in higher plants has been identified in Amaryllis, Haemanthus, tomato, conifer root, pollen of Luffa, pea tendrils, and pollen tube of lily (3,5,13,17,20,21,23) by biochemical and immunological methods. But the concentrations of actin in plant are lower than they are in animal cytoplasmic tissues (14). So the biochemical and physiological studies of plant actomyosin are limited, unlike the cases in other nonmuscle cells such as slime molds and Acanthamoeba castellanii. However, we found that pollen is a rich source of actin for purification. We have developed an efficient method to prepare sufficient quantities of pure actin for biochemical and physiological studies such as the conformational changes during the polymerization of actin and the reassembly of microfilaments in vitro. Here we describe this method, which includes acetone powder preparation, ammonium sulfate fractionation, DEAE-cellulose chromatography, and Sephacryl S-200 gel filtration. Furthermore, the pollen actin w...

show abstract

Plants contain highly divergent actin isovariants

McLean

Huang

McKinney

et al. 1990

Cell Motil. Cytoskeleton

View full text Add to dashboard Cite

Actin protein isovariants have been identified in animals with distinct cytoplasmic or muscle specific patterns of expression. Analysis of vascular plant actin gene sequences suggests that an even greater diversity should exist within the plant actin protein families, but previous studies on plant proteins have not demonstrated the presence of multiple actin isovariants. Antibodies recognizing a conserved amino-terminal plant actin peptide, a family of plant actin peptides from a variable region, and two monoclonal antibodies to conserved epitopes within animal actins were used to identify isovariants of soybean actin resolved by two-dimensional isoelectric focusing (IEF) sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Approximately six to eight actin isovariants with pI values ranging from 5.1 to 5.8 have been identified from soybean hypocotyls, stems, leaves, and roots with varying amounts of most isovariants present in all four organs. Acidic isovariants were present in much higher levels in leaves and stems. Antisera with lambda-class actin specificity detected a subset of three isovariants in all organs examined. One monoclonal and one antipeptide antisera are shown to react well with a wide variety of plant actin isovariants. Similar patterns of actin isovariants were detected in the distant angiosperms, Arabidopsis, petunia, and maize. It is likely that many of these diverse classes of isovariants have been preserved throughout vascular plant evolution and reflect the ancient diversity within plant actin gene families. The extreme difference among isovariants implies the presence of a complex actin-based cytoskeletal system in plants.

show abstract

Diversity of plant actins

Cited by 36 publications

References 27 publications

Actin Purified from Maize Pollen Functions in Living Plant Cells.

Actin Purified from Maize Pollen Functions in Living Plant Cells.

Purification and Characterization of Actin from Maize Pollen

Plants contain highly divergent actin isovariants

Contact Info

Product

Resources

About