Molecular Cloning and Characterization of NESP55, a Novel Chromogranin-like Precursor of a Peptide with 5-HT1B Receptor Antagonist Activity*
- Rudolf Ischia‡,
- Paola Lovisetti-Scamihorn‡§,
- Ruth Hogue-Angeletti,¶,
- Martin Wolkersdorfer,
- Hans Winkler and
- Reiner Fischer-Colbrie∥
- From the Department of Pharmacology, University of Innsbruck, A-6020 Innsbruck, Austria and the
- ¶ Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
- ↵∥To whom correspondence should be addressed: Dept. of Pharmacology, University of Innsbruck, Peter-Mayr-Str. 1a, A-6020 Innsbruck, Austria. Tel.: 43-512-507-3720; Fax: 43-512-507-2868; E-mail: fischer-colbrie{at}uibk.ac.at.
Abstract
The chromogranins comprise a class of acidic proteins that are secreted from large dense core vesicles and expressed in neuronal and endocrine tissues. We describe here the molecular characterization of NESP55 (neuroendocrine secretory protein of Mr 55,000), a novel member of the chromogranins. Several NESP55 cDNA clones were isolated from bovine chromaffin cell libraries. The cDNA sequence of NESP55 totals 1499 nucleotides. All of the clones that were isolated contained in their 3′-untranslated mRNA a sequence that was homologous to exon 2 of the G-protein Gsα. The open reading frame encodes for an acidic and hydrophilic protein of 241 amino acids with a predicted molecular mass of 27,494 Da. An antiserum directed against the C terminus of NESP55 labeled a band of Mr 55,000 with an acidic pI ranging from 4.4 to 5.2 in one- and two-dimensional immunoblots of secretory proteins from chromaffin granules. NESP55 is localized within the cell to the large dense secretory vesicles and is expressed, apart from the adrenal medulla, in the anterior and posterior pituitary and various regions of the brain. For the physiological function, one interesting factor has emerged. NESP55 is proteolytically processed within the chromaffin granule to smaller peptides that might be physiologically active. One tetrapeptide, Leu-Ser-Ala-Leu (LSAL), present in the NESP55 sequence and flanked by arginine residues suitable for cleavage by prohormone convertases, has been identified recently as an endogenous antagonist of the serotonergic 5-HT1B receptor subtype. Alterations in the serotonergic system are thought to play an important role in mental disorders, especially depression, and might be related to abnormal ethanol consumption. It is tempting to speculate that increased expression of NESP55 or its proteolytically derived peptide LSAL might contribute to the pathophysiology of the serotonergic transmission.
Footnotes
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↵‡ Both authors contributed equally to this publication and are listed in alphabetical order.
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↵§ This work was done as part of a master's thesis.
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↵* This work was supported by a grant from the Austrian Science Foundation and Dr. Legerlotz Stiftung (to R. F.-C.). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U77614 [GenBank].
- Received November 15, 1996.
- © 1997 by The American Society for Biochemistry and Molecular Biology, Inc.
