CA2+ BINDING PROTEIN CALRETICULIN IN CHLAMYDOMONAS REINHARDTII (CHLOROPHYTA): BIOCHEMICAL CHARACTERIZATION, DIFFERENTIAL EXPRESSION DURING SEXUAL REPRODUCTION, AND PHYLOGENETIC ANALYSIS
| Autor: | Paola Dainese, Anna Zuppini, Flavio Meggio, Roberto Barbato, William Martin, Elisabetta Bergantino, Paola Mariani |
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| Rok vydání: | 1999 |
| Předmět: |
Chlamydomonas reinhardtii
endoplasmic reticulum Ca2+ binding proteins calreticulin Messenger RNA medicine.diagnostic_test biology Endoplasmic reticulum Binding protein Chlamydomonas Plant Science Aquatic Science biology.organism_classification Molecular biology Western blot Biochemistry medicine biology.protein Peptide sequence Calreticulin |
| Zdroj: | Journal of Phycology. 35:1224-1232 |
| ISSN: | 0022-3646 |
| DOI: | 10.1046/j.1529-8817.1999.3561224.x |
| Popis: | The occurrence of calreticulin, the main Ca2+ binding protein in the endoplasmic reticulum of eukaryotic cells, was investigated in the unicellular green alga Chlamydomonas reinhardtii Dangeard. The biochemical characterization of a diethylaminoethyl purified extract highlighted the presence, on SDS-PAGE, of a 55-kDa protein that stained blue with the Stains All dye, a diagnostic feature of acidic Ca2+ binding proteins. Immunoblot analyses revealed a strong cross-reaction of the Chlamydomonas reinhardtii protein with antibodies to plant calreticulins and the endoplasmic reticulum retention signal HDEL. Furthermore, the 55-kDa protein bound [45Ca2+] and had an acidic isoelectric point (pI = 4.9) but was neither glycosylated nor phosphorylated. N-terminal sequencing revealed strong amino acid sequence similarity to calreticulin from other sources. The presence of calreticulin in Chlamydomonas reinhardtii suggested that an endoplasmic reticulum Ca2+ buffering mechanism was present in this unicellular chlorophyte. The data suggest an early origin and high conservation of endoplasmic-reticulum-mediated Ca2+ functions in eukaryotes, whereby specific posttranslational modifications of the proteinhave been specifically acquired in different lineages of photosynthetic eukaryotes. Moreover, northern and western blot analysis experiments showed a regulation of calreticulin expression during Chlamydomonas sexual reproduction with a high abundance of calreticulin mRNA and protein in reproductive cells. |
| Databáze: | OpenAIRE |
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