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Plant Rac-Like Gtpases Are Activated By Auxin And Mediate Auxin-Responsive Gene Expression, L. Z. Tao, Alice Cheung, H. M. Wu
Plant Rac-Like Gtpases Are Activated By Auxin And Mediate Auxin-Responsive Gene Expression, L. Z. Tao, Alice Cheung, H. M. Wu
Alice Cheung
The auxin indole-3-acetic acid is a key plant hormone essential for a broad range of growth and developmental processes. Here, we show that auxin activates Rac-like GTPases (referred to as Rac/Rop GTPases), and they in turn stimulate auxin-responsive gene expression. In particular, we show that overexpressing a wild-type tobacco Rac/Rop GTPase, NtRac1, and its constitutively active mutant form activates auxin-responsive gene expression. On the other hand, overexpressing dominant-negative NtRac1 and Rac-negative regulators, or reducing the endogenous NtRac1 level, suppresses auxin-induced gene expression. Furthermore, overexpression of NtRac1 activity or suppression of its expression in transgenic seedlings induces phenotypes that are similar …
The Regulation Of Actin Organization By Actin-Depolymerizing Factor In Elongating Pollen Tubes, C. Y. Chen, E. I. Wong, L. Vidali, A. Estavillo, P. K. Hepler, H. M. Wu, Alice Cheung
The Regulation Of Actin Organization By Actin-Depolymerizing Factor In Elongating Pollen Tubes, C. Y. Chen, E. I. Wong, L. Vidali, A. Estavillo, P. K. Hepler, H. M. Wu, Alice Cheung
Alice Cheung
Pollen tube elongation is a polarized cell growth process that transports the male gametes from the stigma to the ovary for fertilization inside the ovules. Actomyosin-driven intracellular trafficking and active actin remodeling in the apical and subapical regions of pollen tubes are both important aspects of this rapid tip growth process. Actin-depolymerizing factor (ADF) and cofilin are actin binding proteins that enhance the depolymerization of microfilaments at their minus, or slow-growing, ends. A pollen-specific ADF from tobacco, NtADF1, was used to dissect the role of ADF in pollen tube growth. Overexpression of NtADF1 resulted in the reduction of fine, axially …
Trp-Dependent Auxin Biosynthesis In Arabidopsis: Involvement Of Cytochrome P450s Cyp79b2 And Cyp79b3, Yunde Zhao, Anna K. Hull, Neeru R. Gupta, Kendrick A. Goss, José Alonso, Joseph R. Ecker, Jennifer Normanly, Joanne Chory, John L. Celenza
Trp-Dependent Auxin Biosynthesis In Arabidopsis: Involvement Of Cytochrome P450s Cyp79b2 And Cyp79b3, Yunde Zhao, Anna K. Hull, Neeru R. Gupta, Kendrick A. Goss, José Alonso, Joseph R. Ecker, Jennifer Normanly, Joanne Chory, John L. Celenza
Jennifer Normanly
The plant hormone auxin regulates many aspects of plant growth and development. Although several auxin biosynthetic pathways have been proposed, none of these pathways has been precisely defined at the molecular level. Here we provide in planta evidence that the two Arabidopsis cytochrome P450s, CYP79B2 and CYP79B3, which convert tryptophan (Trp) to indole-3-acetaldoxime (IAOx) in vitro, are critical enzymes in auxin biosynthesis in vivo. IAOx is thus implicated as an important intermediate in auxin biosynthesis. Plants overexpressing CYP79B2 contain elevated levels of free auxin and display auxin overproduction phenotypes. Conversely, cyp79B2 cyp79B3 double mutants have reduced levels of IAA and …
Flexibility Of Biv Tar-Tat: Models Of Peptide Binding, M Hsieh, E D. Collins, T Blomquist, Brooke Lustig
Flexibility Of Biv Tar-Tat: Models Of Peptide Binding, M Hsieh, E D. Collins, T Blomquist, Brooke Lustig
Brooke S. Lustig
No abstract provided.
Familial Als-Associated Mutations Decrease The Thermal Stability Of Distinctly Metallated Species Of Human Copper/Zinc Superoxide Dismutase, Daryl K. Eggers, J. A. Rodriguez, J. S. Valentine, J. A. Roe, A. Tiwari, R. H. Brown, L. J. Hayward
Familial Als-Associated Mutations Decrease The Thermal Stability Of Distinctly Metallated Species Of Human Copper/Zinc Superoxide Dismutase, Daryl K. Eggers, J. A. Rodriguez, J. S. Valentine, J. A. Roe, A. Tiwari, R. H. Brown, L. J. Hayward
Daryl K. Eggers
We report the thermal stability of wild type (WT) and 14 different variants of human copper/zinc superoxide dismutase (SOD1) associated with familial amyotrophic lateral sclerosis (FALS). Multiple endothermic unfolding transitions were observed by differential scanning calorimetry for partially metallated SOD1 enzymes isolated from a baculovirus system. We correlated the metal ion contents of SOD1 variants with the occurrence of distinct melting transitions. Altered thermal stability upon reduction of copper with dithionite identified transitions resulting from the unfolding of copper-containing SOD1 species. We demonstrated that copper or zinc binding to a subset of “WT-like” FALS mutants (A4V, L38V, G41S, G72S, D76Y, …