Calphotin: a Drosophila photoreceptor cell calcium-binding protein
Abstract
Monoclonal antibody 23E9 identifies a calcium-binding protein, calphotin, in photoreceptor cells of the Drosophila melanogaster compound eyes and ocelli. The antigen is restricted to a defined cytoplasmic region; it is not present in the rhabdomeres, nuclei, mitochondria, or rough endoplasmic reticulum. A corresponding cDNA recognizes a 3-kb mRNA with retinal specificity similar to the antigen and maps to band 86E/F-87A/B on chromosome 3. An open reading frame of 2595 bp encodes an estimated 85-kDa protein of unusual amino acid composition, with > 50% proline, alanine, and valine and very few basic residues. The C-terminal segment contains a leucine zipper motif uninterrupted by prolines. We found no significant similarities with the GenBank or National Biomedical Resource Foundation data bases. The location of the protein within a distinct cytoplasmic region suggests that it might function as a calcium-sequestering "sponge" to regulate the amount of free cytoplasmic calcium.
Additional Information
© 1993 National Academy of Sciences. Contributed by Seymour Benzer, October 22, 1992. We thank Dennis Ballinger for exchange of results and manuscripts, Kent McDonald and Mary Morphew for quick-freeze specimen preparation, Robert Buchanan for help in chromosomal localization, and Rosalind Young for excellent technical assistance. J.H.M. was supported by a postdoctoral fellowship from the National Institutes of Health. This work was supported in part by Grants AG05142 and MH39145 (C.A.M.) and EY09278 (S.B.) from the National Institutes of Health and Grant 8908154 (S.B.) from the National Science Foundation. The sequence reported in this paper has been deposited in the GenBank data base (accession no. L02111). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Attached Files
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Additional details
- PMCID
- PMC45908
- Eprint ID
- 93371
- Resolver ID
- CaltechAUTHORS:20190228-160707825
- NIH Postdoctoral Fellowship
- NIH
- AG05142
- NIH
- MH39145
- NIH
- EY09278
- NSF
- MCB-8908154
- Created
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2019-03-01Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field