A prolactin-inducible gene product which is a member of the calpactin/lipocortin family.
The major PRL-inducible gene product from pigeon cropsac was cloned from lambda gt11 and sequenced by chain termination. The sequence of pGcp35 includes an open reading frame which yields a polypeptide which highly similar to mammalian calpactin II (lipocortin I). Like the other calpactins, the deduced protein (cp35) consists of a 4-fold repeating structure which has a conserved core characteristic of a large group of calcium-dependent membrane-binding proteins. PRL-stimulated cropsac expresses a calcium-dependent membrane-binding protein which is the proper size for endogenous cp35. Detailed comparison of the sequences of cp35 and human calpactin II shows that the only substantial sequence dissimilarity is a domain encoding amino acids between residues 20 and 40 which includes a tyrosine phosphorylation site in the human molecule, along with other residues of possible physiological significance. These results raise the possibility that calpactins are regulated by PRL in other tissues; and, that the sequences of the avian form and the mammalian form may have selectively diverged to yield different regulatory mechanisms.
Horseman
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Biology Department, Marquette University, Milwaukee, Wisconsin 53233.
D000595:Amino Acid Sequence; D000818:Animals; D017302:Annexins; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D010856:Columbidae; D003426:Crop, Avian / Q000378:metabolism; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D005796:Genes / Q000187:drug effects*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010740:Phospholipases / Q000037:antagonists & inhibitors; D011388:Prolactin / Q000494:pharmacology*; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D017302:Annexins; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; C060529:cp35 protein, Columba livia; D011388:Prolactin; D004247:DNA; D010740:Phospholipases