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Procollagen binds to both prolyl 4‐hydroxylase/protein disulfide isomerase and HSP47 within the endoplasmic reticulum in the absence of ascorbate
Author(s) -
Hosokawa Nobuko,
Nagata Kazuhiro
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01713-5
Subject(s) - procollagen peptidase , endoplasmic reticulum , protein disulfide isomerase , ascorbic acid , biochemistry , hydroxylation , chemistry , chaperone (clinical) , enzyme , biology , microbiology and biotechnology , medicine , food science , pathology
In cells, only properly folded procollagen trimers are secreted from the endoplasmic reticulum (ER), while improperly folded abnormal procollagens are retained within the ER. Ascorbic acid is a co‐factor in procollagen hydroxylation, which in turn is required for trimer formation. We examined chaperone proteins which bound to procollagen in the absence of ascorbic acid, a model which mimics the human disease scurvy at the cellular level. We found that both prolyl 4‐hydroxylase (P4‐H)/protein disulfide isomerase (PDI) and HSP47 bound to procollagen in the absence of ascorbic acid. However, the binding of PDI to procollagen decreased when HSP47 was co‐transfected, suggesting that HSP47 and PDI compete for binding to procollagen. These data indicate that P4‐H/PDI and HSP47 have cooperative but distinct chaperone functions during procollagen biosynthesis.