Autoinhibition of a calmodulin-dependent calcium pump involves a structure in the stalk that connects the transmembrane domain to the ATPase catalytic domain.

The regulation of Ca(2+)-pumps is important for controlling [Ca(2+)] in the cytosol and organelles of all eukaryotes. Here, we report a genetic strategy to identify residues that function in autoinhibition of a novel calmodulin-activated Ca(2+)-pump with an N-terminal regulatory domain (isoform ACA2 from Arabidopsis). Mutant pumps with constitutive activity were identified by complementation of a yeast (K616) deficient in two Ca(2+)-pumps.

Characterization of the growth and auxin physiology of roots of the tomato mutant, diageotropica.

Roots of the tomato (Lycopersicon esculentum, Mill.) mutant (diageotropica (dgt) exhibit an altered phenotype. These roots are agravitropic and lack lateral roots.

Investigation of Gene Expression, Growth Kinetics, and Wall Extensibility during Brassinosteroid-Regulated Stem Elongation.

Brassinosteroids promote stem elongation in a variety of plants but little is known about the mechanism of action of these plant growth regulators. We investigated a number of physiological and molecular parameters associated with brassinosteroid-enhanced elongation. Continuous growth recordings of soybean (Glycine max L.

The Acid Growth Theory of auxin-induced cell elongation is alive and well.

Plant cells elongate irreversibly only when load-bearing bonds in the walls are cleaved. Auxin causes the elongation of stem and coleoptile cells by promoting wall loosening via cleavage of these bonds. This process may be coupled with the intercalation of new cell wall polymers.

The pH profile for acid-induced elongation of coleoptile and epicotyl sections is consistent with the acid-growth theory.

The acid-growth theory predicts that a solution with a pH identical to that of the apoplast of auxintreated tissues (4.5-5.0) should induce elongation at a rate comparable to that of auxin.