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A calmodulin-dependent protein kinase from lower eukaryote Physarum polycephalum
Akio Nakamura1, Yuki Hanyuda, Tuyoshi Okagaki
1Department of Molecular and Cellular Pharmacology, Faculty of Medicine, Gunma University Graduate School of Medicine, Gunma 371-8511, Japan. gacho@med.gunma-u.ac.jp
Biochemical and Biophysical Research Communications
|February 15, 2005
Summary
Researchers cloned a calmodulin-dependent protein kinase gene from Physarum. This kinase phosphorylates myosin II light chain at Ser 18, crucial for Physarum cell function.
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Biology
Background:
- Calmodulin (CaM)-dependent protein kinases regulate diverse cellular processes.
- Myosin II phosphorylation is critical for cellular functions in organisms like Physarum.
Purpose of the Study:
- To clone and characterize a CaM-dependent protein kinase from Physarum plasmodia.
- To investigate the kinase's role in phosphorylating myosin II light chain.
Main Methods:
- Polymerase chain reaction (PCR) was used to clone the kinase gene from Physarum poly(A)-RNA.
- The cloned gene was expressed in Escherichia coli for functional analysis.
- Phosphorylation assays and peptide analysis were performed to identify the phosphorylation site.
Main Results:
- A full-length cDNA encoding a 42,519-Da CaM-dependent protein kinase was successfully cloned.
- The expressed Physarum kinase phosphorylated recombinant Physarum myosin II light chain (PLc) in a Ca2+/CaM-dependent manner.
- Serine 18 of PLc was identified as the specific phosphorylation site, confirmed by site-directed mutagenesis.
Conclusions:
- A novel CaM-dependent protein kinase from Physarum has been identified and characterized.
- This kinase plays a role in regulating Physarum myosin II function through phosphorylation of PLc at Ser 18.
- Further research can explore its physiological significance in relation to previously identified kinases.