Calmodulin, calbindin-D28K and calretinin in rat and chicken pineal glands: Immunocytochemical and immunoblotting analysis

Roland Pochet, Jean Van Rampelbergh, Enrico Bastianelli, Linda J. Van Eldik

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In pineal gland, melatonin is synthesized in pinealocytes. Pharmacological studies using calmodulin antagonists suggested that melatonin synthesis was regulated through calmodulin. However, immunohistochemical studies showed that calmodulin could only be detected in pineal glial cells, and not in pinealocytes. To further investigate this discrepancy, we have tried to detect calmodulin not seen by immunohistochemical methods. We have used rat and chicken pineal homogenate supernatants and Triton X-100-treated pellets denatured by sodium dodecyl sulfate, subjected to electrophoresis and immunoblotting using anti-calmodulin antibodies. Two different IgG (#465 and #860) purified from anti-calmodulin sera were used. In rat pineal homogenate supernatants, calmodulin could be detected by immunoblotting using both antibodies. Some calmodulin could also be detected in the Triton-treated pellet fractions, but no additional cross-reacting bands were detected. However, in both chicken pineal homogenate supernatants and Triton-extracted pellets, in addition to a calmodulin immunoreactive band, two other proteins with approximate molecular masses (Mr) of 56 kDa and 60 kDa were detected using anti-calmodulin #465. For comparison, similar immunoblot experiments were performed for detection of calbindin-D28K and calretinin, two other calcium binding proteins expressed in different pineal cell populations. Interestingly, Triton extraction of chicken pineal pellets revealed additional bands cross-reacting with each antibody. Anti-calbindin-D28K cross-reacted strongly with a Mr = 68 kDa protein and weakly with a Mr = 56 kDa protein. Anti-calretinin cross-reacted strongly with a Mr = 93 kDa protein and weakly with a Mr = 56 kDa protein.

Original languageEnglish
Pages (from-to)318-324
Number of pages7
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1223
Issue number3
DOIs
StatePublished - Sep 29 1994

Bibliographical note

Funding Information:
We thank Leon Surardt for excellent technical assistance and Paulette Miroir for typing the manuscript. This work was supported by FRSM (grant no. 3.4517. 92).

Funding

We thank Leon Surardt for excellent technical assistance and Paulette Miroir for typing the manuscript. This work was supported by FRSM (grant no. 3.4517. 92).

FundersFunder number
FRSM3.4517

    Keywords

    • Calcium
    • Calcium binding protein
    • Glial cell
    • Pinealocyte
    • Western blot

    ASJC Scopus subject areas

    • Molecular Biology
    • Cell Biology

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