A SHORT-FORM OF LEPTIN RECEPTOR PERFORMS SIGNAL-TRANSDUCTION

The obese (ob) gene product, leptin, a peptide hormone, which is synth esized in adipocytes, is a satiety factor and is involved in the contr ol of body weight via the regulation of energy homeostasis, Several al ternate spliced isoforms (a-e, as well as others) of the leptin recept or (OBR) have been cloned, all of which, except for OBRe (soluble form ), contain a single transmembrane domain. They share the same extracel lular domain, with homology to the class I cytokine receptor family, T he OBRb, which has longest cytoplasmic domain, is expressed in high le vels in the hypothalamus and is thought to be the only isoform capable of signal transmission. Herein, we report the mRNA expression of imme diate early genes, c-fos, c-jun and jun-B, which are induced by leptin addition, not only in CHO cells expressing the OBRb, but also in cell s expressing one of the short form receptors, OBRa. (C) 1997 Academic Press.