Molecular cloning and expression of serum calcium-decreasing factor (caldecrin).
We previously reported on the purification of a serum calcium-decreasing factor, referred to as caldecrin, from porcine pancreas, that is thought to be a serine protease (Tomomura, A., Fukushige, T., Noda, T., Noikura, T., and Saheki, T. (1992) FEBS Lett. 301, 277-281). In the present study, we purified caldecrin from rat pancreas and determined its primary structure by cDNA cloning. The predicted caldecrin protein is presumed to be synthesized as a preproenzyme of 268 amino acids with a signal peptide of 16 amino acids and an activation peptide of 13 amino acids, and is, with the exception of a central region, almost identical to the reported rat pancreatic elastase IV sequence. The caldecrin gene is selectively expressed in the pancreas, as judged by Northern blot analysis. After expression in BMT-10 cells, immunoreactive caldecrin was found in the culture supernatant, and it inhibited the parathyroid hormone-stimulated 45Ca release from cultured fetal long bones. Catalytic site mutants were synthesized in a baculovirus system, and recombinant mutants also decreased the serum calcium level of mice. These data implicate caldecrin, a protease closely related to elastase IV, in the regulation of blood calcium levels.
Department of Biochemistry, Faculty of Medicine, Kagoshima University, Japan.
A
A
Tomomura
M
M
Tomomura
T
T
Fukushige
M
M
Akiyama
N
N
Kubota
K
K
Kumaki
Y
Y
Nishii
T
T
Noikura
T
T
Saheki
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001681:Biological Assay; D001862:Bone Resorption; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D005333:Fetus; D015870:Gene Expression; D006727:Hormone Antagonists / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009924:Organ Culture Techniques; D009928:Organ Specificity; D010179:Pancreas / Q000737:chemistry / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000096:biosynthesis; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D021382:Protein Sorting Signals / Q000096:biosynthesis; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D013552:Swine
D017931:DNA Primers; D018076:DNA, Complementary; D006727:Hormone Antagonists; D010446:Peptide Fragments; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; C074385:caldecrin; D010196:Pancreatic Elastase; D002118:Calcium