The C-terminal region of the human p23 chaperone modulates its structure and function

Author(s)

Seraphim, Thiago V. ^[1] ; Gava, Lisandra M. ^[2] ; Mokry, David Z. ^[3] ; Cagliari, Thiago C. ^{[3, 4]} ; Barbosa, Leandro R. S. ^[5] ; Ramos, Carlos H. I. ^[3] ; Borges, Julio C. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Fed Univ Sao Carlos UFSCar, Dept Genet & Evolut, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Campinas UNICAMP, Inst Chem, BR-13083970 Campinas, SP - Brazil

^[4] Univ Campinas UNICAMP, Inst Biol, BR-13083970 Campinas, SP - Brazil

^[5] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo - Brazil

• Document type: Journal article
• Source: Archives of Biochemistry and Biophysics; v. 565, p. 57-67, JAN 1 2015.
• Web of Science Citations: 7

Abstract

The p23 protein is a chaperone widely involved in protein homeostasis, well known as an Hsp90 cochaperone since it also controls the Hsp90 chaperone cycle. Human p23 includes a 13-sheet domain, responsible for interacting with Hsp90; and a charged C-terminal region whose function is not clear, but seems to be natively unfolded. p23 can undergo caspase-dependent proteolytic cleavage to form p19 (p231-142), which is involved in apoptosis, while p23 has anti-apoptotic activity. To better elucidate the function of the human p23 C-terminal region, we studied comparatively the full-length human p23 and three C-terminal truncation mutants: p231\_117; p231-131 and p231\_142. Our data indicate that p23 and p19 have distinct characteristics, whereas the other two truncations behave similarly, with some differences to p23 and p19. We found that part of the C-terminal region can fold in an a-helix conformation and slightly contributes to p23 thermal-stability, suggesting that the C-terminal interacts with the 13-sheet domain. As a whole, our results suggest that the C-terminal region of p23 is critical for its structure-function relationship. A mechanism where the human p23 C-terminal region behaves as an activation/inhibition module for different p23 activities is proposed. (C) 2014 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 11/23110-0 - Using isothermal titration calorimetry for the determination of thermodynamic properties of protein-ligand and protein-protein interactions
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/50161-8 - Study of the structure and function of the Hsp90 chaperone with emphasis on its role in cellular homeostasis
• Grantee: Carlos Henrique Inacio Ramos
• Support Opportunities: Research Projects - Thematic Grants