The rough endoplasmic reticulum-resident FK506-binding protein FKBP65 is a molecular chaperone that interacts with collagens.
The rough endoplasmic reticulum-resident FK-506-binding protein FKBP65 can be isolated from chick embryos on a gelatin-Sepharose column, indicating some involvement in the biosynthesis of procollagens. The peptidylprolyl cis-trans-isomerase activity of FKBP65 was previously shown to have only marginal effects on the rate of triple helix formation (Zeng, B., MacDonald, J. R., Bann, J. G., Beck, K., Gambee, J. E., Boswell, B. A., and Bächinger, H. P. (1998) Biochem. J. 330, 109-114). Here we show that FKBP65 is a monomer in solution and acts as a chaperone molecule when tested with two classic chaperone assays: FKBP65 inhibits the thermal aggregation of citrate synthase and is active in the denatured rhodanese refolding and aggregation assay. The chaperone activity is comparable to that of protein-disulfide isomerase, a well characterized chaperone. FKBP65 delays the in vitro fibril formation of type I collagen, indicating that FKBP65 is also able to interact with triple helical collagen, and acts as a collagen chaperone.
Ishikawa
Yoshihiro
Y
Research Department, Shriners Hospital for Children, Portland, Oregon 97239, USA.
Vranka
Janice
J
Wirz
Jackie
J
Nagata
Kazuhiro
K
Bächinger
Hans Peter
HP
D000818:Animals; D002642:Chick Embryo; D002942:Circular Dichroism; D024042:Collagen Type I / Q000378:metabolism*; D018870:Endoplasmic Reticulum, Rough / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D011485:Protein Binding; D017510:Protein Folding; D013379:Substrate Specificity; D022021:Tacrolimus Binding Proteins / Q000737:chemistry / Q000378:metabolism*
D024042:Collagen Type I; D018832:Molecular Chaperones; D022021:Tacrolimus Binding Proteins