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CpKLP1: A CALMODULIN‐BINDING KINESIN‐LIKE PROTEIN FROM CYANOPHORA PARADOXA (GLAUCOPHYTA)
Author(s) -
AbdelGhany Salah E.,
Kugrens Paul,
Reddy A. S. N.
Publication year - 2000
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.2000.00024.x
Subject(s) - biology , calmodulin , kinesin , subfamily , calmodulin binding proteins , binding protein , peptide sequence , biochemistry , microbiology and biotechnology , phylogenetic tree , complementary dna , binding site , genetics , gene , microtubule , enzyme
KCBP (kinesin‐like calmodulin [CaM]‐binding proteins), a member of the carboxy‐terminal kinesin‐like proteins (KLPs), is unique among KLPs in having a CaM‐binding domain (CBD). CaM‐binding KLPs have been identified from flowering plants and the sea urchin. To determine if CaM‐binding KLP is present in phylogenetically divergent protists, we probed Cyanophora paradoxa protein extract with affinity‐purified KCBP antibody. The KCBP antibody detected a polypeptide with a molecular mass of about 133 kDa in the crude extract. In a CaM–Sepharose column‐purified fraction, the same band was detected with both KCBP antibody and biotinylated CaM. In a PCR reaction using degenerate primers corresponding to two conserved regions in the motor domain of kinesin, a 500‐bp fragment (CpKLP1) was amplified from a cDNA library. The predicted amino acid sequence of CpKLP1 showed significant sequence similarity with KCBPs. In phylogenetic analysis, CpKLP1 fell into the KCBP group within the carboxy‐terminal subfamily. These biochemical data, sequence, and phylogenetic analysis strongly suggest the presence of a calmodulin‐binding KLP in C. paradoxa and that it is related to Ca 2 +/calmodulin regulated KLPs from plants. This is the first report on identification of any motor protein in C. paradoxa. Furthermore, our data suggest that CaM‐binding KLPs may have evolved long before the divergence of plants and animals.