Insulin-degrading enzyme activity is modulated by interaction with pyrroline-5-carboxylate reductase 1

Authors

Song, E. S., Camacho-Navas, C., Goswami, A., Nayak, A., Arizaca Maquera, K. A., Chen, J., Stamm, S., Galperin, E., Hersh, L. B., Rodgers, D. W.

Abstract

Insulin-degrading enzyme (IDE, insulysin, insulinase) is a peptidase that hydrolyzes a number of bioactive peptides including insulin and the amyloid beta peptide, making it a promising therapeutic target for diabetes and Alzheimers disease. Aspects of its physiological role are still controversial, however. In an attempt to further define IDEs role in cells, we used co-immunoprecipitation experiments to identify potential IDE interacting proteins. The enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) was found associated with IDE in three different cell lines, and the two proteins colocalize in HeLa cells. Purified PYCR1 activates IDE toward small peptide substrates, suggesting a modulatory role for the interaction in vivo. Modeling suggests that the unstructured N-terminal region of PYCR1 inserts into allosteric sites of IDE, contributing to the observed activation. Deleting this sequence alters, but does eliminate, the interaction between PYCR1 and IDE. Since pyrroline-5-carboxylate reductase 1 is a mitochondrial protein, we posit that their interaction could regulate a previously described mitochondrial pool of IDE, which may serve to degrade mitochondrial targeting sequences or amyloid beta peptide that localizes to that organelle.

Preprint server: bioRxiv
The authors list and abstract were imported from bioRxiv on 21 Jul 2026.

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