FKBP12 physically and functionally interacts with aspartokinase in Saccharomyces cerevisiae.

Journal Article (Journal Article)

The peptidyl-prolyl isomerase FKBP12 was originally identified as the intracellular receptor for the immunosuppressive drugs FK506 (tacrolimus) and rapamycin (sirolimus). Although peptidyl-prolyl isomerases have been implicated in catalyzing protein folding, the cellular functions of FKBP12 in Saccharomyces cerevisiae and other organisms are largely unknown. Using the yeast two-hybrid system, we identified aspartokinase, an enzyme that catalyzes an intermediate step in threonine and methionine biosynthesis, as an in vivo binding target of FKBP12. Aspartokinase also binds FKBP12 in vitro, and drugs that bind the FKBP12 active site, or mutations in FKBP12 surface and active site residues, disrupt the FKBP12-aspartokinase complex in vivo and in vitro.fpr1 mutants lacking FKBP12 are viable, are not threonine or methionine auxotrophs, and express wild-type levels of aspartokinase protein and activity; thus, FKBP12 is not essential for aspartokinase activity. The activity of aspartokinase is regulated by feedback inhibition by product, and genetic analyses reveal that FKBP12 is important for this feedback inhibition, possibly by catalyzing aspartokinase conformational changes in response to product binding.

Full Text

Duke Authors

Cited Authors

  • Alarcón, CM; Heitman, J

Published Date

  • October 1997

Published In

Volume / Issue

  • 17 / 10

Start / End Page

  • 5968 - 5975

PubMed ID

  • 9315655

Pubmed Central ID

  • PMC232445

International Standard Serial Number (ISSN)

  • 0270-7306

Digital Object Identifier (DOI)

  • 10.1128/MCB.17.10.5968


  • eng

Conference Location

  • United States