A Novel Ca2+/CaM-regulated Microtubule Motor Protein from Plants: Role in Trichome Morphogenesis and Cell Division
In recent years Ca2+ has emerged as a key messenger in transducing many hormonal and environmental signals in plants (Hepler and Wayne 1985, Poovaiah and Reddy 1987, Poovaiah and Reddy 1993, Bowler and Chua 1994, Trewavas and Malho 1997, Sander et al 1999). However, the biochemical and molecular events involved in the mode of Ca2+ action are poorly understood. Ca2+ is believed to control many biochemical and molecular processes by interacting with several proteins either directly or through calmodulin (CaM), a highly conserved, multifunctional regulatory protein in eukaryotes (Roberts et al 1986, Snedden and Fromm 1998). Calmodulin action in regulating biochemical and molecular events and ultimately physiological processes involves its interaction with other proteins called CaM-binding proteins. The effect of this interaction usually results in regulation of enzymatic activity/function of the binding protein. In animal systems a large number of CaM-binding proteins have been characterized (Rhoads and Friedberg 1997). In plants, little is known about the number, localization, identity, function and regulation of CaM-binding proteins (Snedden and Fromm 1998, Zielinski 1998). In our attempts to identify interacting protein partners of CaM, we screened expression libraries of Arabidopsis and other plants with labeled CaM. This screening has resulted in isolation of several CaM-binding proteins.
KeywordsCell Plate Motor Domain Dependent ATPase Activity Kinesin Heavy Chain Conventional Kinesin
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