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Identification and purification of a novel 120-kDa protein that recognizes the cAMP-responsive element

Journal Article · · Journal of Biological Chemistry; (USA)
OSTI ID:7025539
;  [1]
  1. Purdue Univ., West Lafayette, IN (USA)
The TGACGTCA (CRE) motif required for function by a number of cellular (somatostatin, enkephalin, alpha-human chorionic gonadotropin) and viral (Ad5 E1A-inducible, HTLV-1 TAX-inducible) genes is the site of interaction of multiple sequence-specific complexes. A protocol has been developed for the fractionation and purification of these activities. We report here the purification from HeLa nuclear extracts of a novel 120-kDa polypeptide which by Southwestern blots, gel retardation, and UV cross-linking assays displays CRE-specific binding. The CRE-affinity purified 120-kDa protein displays properties distinct from those of the 43-kDa CREB/ATF polypeptide. The 120-kDa protein is readily phosphorylated in vitro by protein kinase C but not by protein kinase A, suggesting that this molecule may mediate cellular signals distinct from the cAMP-responsive pathway. In vitro transcription-complementation assays utilizing the purified 120-kDa protein failed to transactivate the cAMP-responsive somatostatin promoter suggesting that the mode of action of this 120-kDa polypeptide may require an activation step distinct from the cAMP-signaling pathway.
OSTI ID:
7025539
Journal Information:
Journal of Biological Chemistry; (USA), Journal Name: Journal of Biological Chemistry; (USA) Vol. 265:6; ISSN JBCHA; ISSN 0021-9258
Country of Publication:
United States
Language:
English