TY - JOUR
T1 - OLA1 protects cells in heat shock by stabilizing HSP70
AU - Mao, R. F.
AU - Rubio, V.
AU - Chen, H.
AU - Bai, L.
AU - Mansour, O. C.
AU - Shi, Z. Z.
N1 - Funding Information:
Acknowledgements. We are grateful to Dr. Brian E. O’Neill (The Methodist Hospital) for assistance preparing the manuscript. We thank Dr. Junn Yanagisawa (University of Tsukuba) for providing CHIP expression constructs. We thank Dr. Sean Yu (Epoch Life Science) for critical help in cloning of DNA constructs, expression of recombinant OLA1 protein, and purification of anti-human OLA1 antibody and Dr. Jiawei Zhang (Zhejiang University) for establishing the stable knockdown cell lines. We thank Ms. Sunae Kim for assistance in ordering reagents. Intracellular co-localization imaging was performed at The Methodist Hospital Research Institute (TMHRI) Advanced Cellular and Tissue Microscope Core Facility. This work was supported by NIH grant R01CA155069 (ZS) and TMHRI Scholar Award (ZS).
PY - 2013/2
Y1 - 2013/2
N2 - The heat-shock response is an evolutionarily conserved cellular defense mechanism against environmental stresses, characterized by the rapid synthesis of heat-shock proteins (HSPs). HSP70, a highly inducible molecular chaperone, assists in refolding or clearance of damaged proteins, thereby having a central role in maintaining intracellular homeostasis and thermotolerance. To date, induction of HSP70 expression has been described extensively at the transcriptional level. However, post-translational regulation of HSP70, such as protein stability, is only partially understood. In this study, we investigated the role of OLA1 (Obg-like ATPase 1), a previously uncharacterized cytosolic ATPase, in regulating the turnover of HSP70. Downregulation of OLA1 in mammalian cells by either RNAi or targeted gene disruption results in reduced steady-state levels of HSP70, impaired HSP70 induction by heat, and functionally, increased cellular sensitivity to heat shock. Conversely, overexpression of OLA1 correlates with elevated HSP70 protein levels and improved thermal resistance. Proteinprotein interaction assays demonstrated that binding of OLA1 to the HSP70 carboxyl terminus variable domain hinders the recruitment of CHIP (C-terminus of Hsp70-binding protein), an E3 ubiquitin ligase for HSP70, and thus prevents HSP70 from the CHIPmediated ubiquitination. These findings suggest a novel molecular mechanism by which OLA1 stabilizes HSP70, leading to upregulation of HSP70 as well as increased survival during heat shock.
AB - The heat-shock response is an evolutionarily conserved cellular defense mechanism against environmental stresses, characterized by the rapid synthesis of heat-shock proteins (HSPs). HSP70, a highly inducible molecular chaperone, assists in refolding or clearance of damaged proteins, thereby having a central role in maintaining intracellular homeostasis and thermotolerance. To date, induction of HSP70 expression has been described extensively at the transcriptional level. However, post-translational regulation of HSP70, such as protein stability, is only partially understood. In this study, we investigated the role of OLA1 (Obg-like ATPase 1), a previously uncharacterized cytosolic ATPase, in regulating the turnover of HSP70. Downregulation of OLA1 in mammalian cells by either RNAi or targeted gene disruption results in reduced steady-state levels of HSP70, impaired HSP70 induction by heat, and functionally, increased cellular sensitivity to heat shock. Conversely, overexpression of OLA1 correlates with elevated HSP70 protein levels and improved thermal resistance. Proteinprotein interaction assays demonstrated that binding of OLA1 to the HSP70 carboxyl terminus variable domain hinders the recruitment of CHIP (C-terminus of Hsp70-binding protein), an E3 ubiquitin ligase for HSP70, and thus prevents HSP70 from the CHIPmediated ubiquitination. These findings suggest a novel molecular mechanism by which OLA1 stabilizes HSP70, leading to upregulation of HSP70 as well as increased survival during heat shock.
KW - CHIP
KW - Heat-shock response
KW - Homeostasis
KW - HSP70
KW - OLA1
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U2 - 10.1038/cddis.2013.23
DO - 10.1038/cddis.2013.23
M3 - Article
C2 - 23412384
AN - SCOPUS:84875969101
SN - 2041-4889
VL - 4
JO - Cell Death and Disease
JF - Cell Death and Disease
IS - 2
ER -