A Novel Serum Protein Similar to C1q, Produced Exclusively in Adipocytes (*)
- Philipp E. Scherer(1)(§),
- Suzanne Williams(2),
- Michael Fogliano(2),
- Giulia Baldini(1)(¶) and
- Harvey F. Lodish(1)(3)(**)
- From the (1) Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142-1479
- (2) Pfizer Central Research, Groton, Connecticut 06340, and the
- (3) Department of Biology, Massachusetts Institute of Technology, Cambridge Massachusetts 02139
- ** To whom correspondence should be addressed. Tel.: 617-258-5216; Fax: 617-258-9872; lodish{at}wi.mit.edu.
Abstract
We describe a novel 30-kDa secretory protein, Acrp30 (adipocyte complement-related protein of 30 kDa), that is made exclusively in adipocytes and whose mRNA is induced over 100-fold during adipocyte differentiation. Acrp30 is structurally similar to complement factor C1q and to a hibernation-specific protein isolated from the plasma of Siberian chipmunks; it forms large homo-oligomers that undergo a series of post-translational modifications. Like adipsin, secretion of Acrp30 is enhanced by insulin, and Acrp30 is an abundant serum protein. Acrp30 may be a factor that participates in the delicately balanced system of energy homeostasis involving food intake and carbohydrate and lipid catabolism. Our experiments also further corroborate the existence of an insulin-regulated secretory pathway in adipocytes.
Footnotes
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↵§ Supported by a fellowship from the Swiss National Science Foundation.
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↵¶ Supported by Fellowship 301033 from the Juvenile Diabetes Foundation. Present address: Dept. of Anatomy and Physiology, College of Physicians and Surgeons 12-404, 630W 168th St., Columbia University, New York, NY 10032.
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↵* This work was supported in part by National Institutes of Health Grant DK 47618 and a grant from Pfizer Corp. (to H. F. L.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵1 The abbreviations used are:
- Acrp30
-
adipocyte complement-related protein of 30 kDa
- Endo H
-
endoglycosidase H
- BS
-
bis(sulfosuccinimidyl)suberate
- kb
-
kilobase(s)
- bp
-
base pair(s)
- PBS
-
phosphate-buffered saline
- PAGE
-
polyacrylamide gel electrophoresis.
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- Received July 25, 1995.
- Revision received September 12, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
