RRC ID 58260
Author Tsuji A, Kikuchi Y, Sato Y, Koide S, Yuasa K, Nagahama M, Matsuda Y.
Title A proteomic approach reveals transient association of reticulocalbin-3, a novel member of the CREC family, with the precursor of subtilisin-like proprotein convertase, PACE4.
Journal Biochem J
Abstract SPCs (subtilisin-like proprotein convertases) are a family of seven structurally related serine endoproteases that are involved in the proteolytic activation of proproteins. In an effort to examine the substrate protein for PACE4 (paired basic amino-acid-cleaving enzyme-4), an SPC, a potent protein inhibitor of PACE4, an alpha1-antitrypsin RVRR (Arg-Val-Arg-Arg) variant, was expressed in GH4C1 cells. Ectopic expression of the RVRR variant caused accumulation of the 48 kDa protein in cells. Sequence analysis indicates that the 48 kDa protein is a putative Ca2+-binding protein, RCN-3 (reticulocalbin-3), which had previously been predicted by bioinformatic analysis of cDNA from the human hypothalamus. RCN-3 is a member of the CREC (Cab45/reticulocalbin/ERC45/calumenin) family of multiple EF-hand Ca2+-binding proteins localized to the secretory pathway. The most interesting feature of the RCN-3 sequence is the presence of five Arg-Xaa-Xaa-Arg motifs, which represents the target sequence of SPCs. Biosynthetic studies showed that RCN-3 is transiently associated with proPACE4, but not with mature PACE4. Inhibition of PACE4 maturation by a Ca2+ ionophore resulted in accumulation of the proPACE4-RCN-3 complex in cells. Furthermore, autoactivation and secretion of PACE4 was increased upon co-expression with RCN-3. Our findings suggest that selective and transient association of RCN-3 with the precursor of PACE4 plays an important role in the biosynthesis of PACE4.
Volume 396(1)
Pages 51-9
Published 2006-5-15
DOI 10.1042/BJ20051524
PII BJ20051524
PMID 16433634
PMC PMC1449992
MeSH Adenoma / pathology Amino Acid Sequence Animals COS Cells Calcium-Binding Proteins / genetics Calcium-Binding Proteins / metabolism* Cell Line Cell Line, Tumor / metabolism Chlorocebus aethiops Enzyme Activation Furin / antagonists & inhibitors Humans Kidney / cytology Molecular Sequence Data Neoplasm Proteins / metabolism Pituitary Neoplasms / pathology Proprotein Convertase 5 / antagonists & inhibitors Proprotein Convertases Protein Binding Protein Precursors / genetics Protein Precursors / metabolism* Proteomics Rats Recombinant Fusion Proteins / metabolism Sequence Alignment Sequence Homology, Amino Acid Serine Endopeptidases / genetics Serine Endopeptidases / metabolism* Transfection alpha 1-Antitrypsin / chemistry alpha 1-Antitrypsin / genetics alpha 1-Antitrypsin / metabolism
IF 4.097
Times Cited 24
DNA material Human Reticulocalbin 3 (RDB03412)