We identified one of these as a plant- specific microtubule motor protein. Functional analysis of this protein suggests its involvement in cell division. Since the early stages of tuberization involve active cell division at the stolon tip, it is likely that this calmodulin-binding protein plays an important role in tuberization. The second cDNA also encodes a novel calmodulin-binding protein. Analysis of truncated proteins by this cDNA showed two independent calmodulin-binding domains.
Sequence analysis indicates that it is a nuclear protein.
Knowledge obtained from these studies should be useful in manipulating tuberization process in potato. Furthermore, these studies will provide important information regarding the function of these new calmodulin-binding proteins in calcium signaling. 1999 Calcium is implicated in regulating many aspects of plant growth and development including tuberization in potato. Calmodulin, a ubiquitous and multifunctional calcium-binding protein in eukaryotes, regulates many diverse cellular processes by modulating the activity of the proteins that interact with it. We have isolated two novel members of calmodulin-binding proteins from developing tubers, and analyzed the expression and function of one of the proteins.