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CC BY V4.0, Open Access
Journal article
Interaction of Plant Chimeric Calcium/Calmodulin-dependent Protein Kinase with a Homolog of Eukaryotic Elongation Factor-1α
The Journal of biological chemistry, Vol.274(17), pp.12001-12008
04/23/1999
Handle:
https://hdl.handle.net/2376/106473
PMID: 10207022
Abstract
A chimeric Ca 21 /calmodulin-dependent protein ki-nase (CCaMK) was previously cloned and characterized in this laboratory. To investigate the biological functions of CCaMK, the yeast two-hybrid system was used to isolate genes encoding proteins that interact with CCaMK. One of the cDNA clones obtained from the screening (LlEF-1a1) has high similarity with the eu-karyotic elongation factor-1a (EF-1a). CCaMK phospho-rylated LlEF-1a1 in a Ca 21 /calmodulin-dependent manner. The phosphorylation site for CCaMK (Thr-257) was identified by site-directed mutagenesis. Interestingly, Thr-257 is located in the putative tRNA-binding region of LlEF-1a1. An isoform of Ca 21-dependent protein ki-nase (CDPK) phosphorylated multiple sites of LlEF-1a1 in a Ca 21-dependent but calmodulin-independent manner. Unlike CDPK, CCaMK phosphorylated only one site, and this site is different from CDPK phosphoryla-tion sites. This suggests that the phosphorylation of EF-1a by these two kinases may have different functional significance. Although the phosphorylation of LlEF-1a1 by CCaMK is Ca 21 /calmodulin-dependent, in vitro binding assays revealed that CCaMK binds to LlEF-1a1 in a Ca 21-independent manner. This was further substantiated by coimmunoprecipitation of CCaMK and EF-1a using the protein extract from lily anthers. Dissociation of CCaMK from EF-1a by Ca 21 and phosphorylation of EF-1a by CCaMK in a Ca 21 /calmod-ulin-dependent manner suggests that these interactions may play a role in regulating the biological functions of EF-1a. Ca 21 is a universal second messenger that regulates diverse developmental and physiological processes in plants (1). One of the major mechanisms decoding the change of intracellular Ca 21 and transducing Ca 21 signal is the action of Ca 21-modulated proteins. Calmodulin (CaM) 1 is a highly conserved and the most widely distributed Ca 21-binding protein (2). CaM is believed to be a primary receptor for intracellular Ca 21 and
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Details
- Title
- Interaction of Plant Chimeric Calcium/Calmodulin-dependent Protein Kinase with a Homolog of Eukaryotic Elongation Factor-1α
- Creators
- Wuyi WangB. W Poovaiah
- Publication Details
- The Journal of biological chemistry, Vol.274(17), pp.12001-12008
- Academic Unit
- Department of Horticulture
- Identifiers
- 99900546671401842
- Language
- English
- Resource Type
- Journal article