TWISTED DWARF1 Mediates the Action of Auxin Transport Inhibitors on Actin Cytoskeleton Dynamics.

Plant growth and architecture is regulated by the polar distribution of the hormone auxin. Polarity and flexibility of this process is provided by constant cycling of auxin transporter vesicles along actin filaments, coordinated by a positive auxin-actin feedback loop. Both polar auxin transport and vesicle cycling are inhibited by synthetic auxin transport inhibitors, such as 1-N-naphthylphthalamic acid (NPA), counteracting the effect of auxin; however, underlying targets and mechanisms are unclear.

Parvulin 17-catalyzed Tubulin Polymerization Is Regulated by Calmodulin in a Calcium-dependent Manner.

Recently we have shown that the peptidyl-prolyl cis/trans isomerase parvulin 17 (Par17) interacts with tubulin in a GTP-dependent manner, thereby promoting the formation of microtubules. Microtubule assembly is regulated by Ca(2+)-loaded calmodulin (Ca(2+)/CaM) both in the intact cell and under in vitro conditions via direct interaction with microtubule-associated proteins. Here we provide the first evidence that Ca(2+)/CaM interacts also with Par17 in a physiologically relevant way, thus preventing Par17-promoted microtubule assembly.

¹H, ¹³C and ¹⁵N resonance assignments of human parvulin 17.

A 25-residue elongation at the N-terminus endows parvulin 17 (Par17) with altered functional properties compared to parvulin 14 (Par14), such as an enhanced influence on microtubule assembly. Therefore the three-dimensional structure of this N-terminal elongation is of particular interest. Here, we report the nearly complete (1)H, (13)C and (15)N chemical shift assignments of Par17.

NMR assignments of the FKBP-type PPIase domain of FKBP42 from Arabidopsis thaliana.

The Atfkbp42 gene is associated with reduced and disoriented growth of Arabidopsis thaliana. Resonance assignments are reported for the FKBP-type PPIase domain of AtFKBP42. Signal intensities reveal an additional structure element that is atypical for such FKBP domains.