Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2016 Dec 2;6(12):e503. doi: 10.1038/bcj.2016.112

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2016 The Author(s)

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

PMC Copyright notice

The i-prot has distinct features compared with the constitutional proteasome. The i-prot is formed when the β1c, β2c and β5c subunits of the c-prot are replaced by β1i and β5i, respectively. The expression of these subunits is promoted – at least in part – by IFNγ and TNFα signaling. Once expressed, β1i and β5i associate with the chaperone protein POMP, which facilitates their incorporation into the proteasome. In AML, however, it has been demonstrated that β1i and β5i are sequestered by PRAS40, a component of mTORC1. Once mTORC1 is activated by any of a number of methods (hyperactivation of mTORC1 is a feature of numerous malignancies), it phosphorylates PRAS40 and releases β1i and β5i, thus facilitating the assembly of the i-prot. The incorporation of these different subunits alters the proteolytic substrate selectivity of the i-prot, granting the i-prot distinct functions as compared with the c-prot.