TY - JOUR
T1 - Structural and biological interaction of HSC-70 protein with phosphatidylserine in endosomal microautophagy
AU - Morozova, Kateryna
AU - Clement, Cristina C.
AU - Kaushik, Susmita
AU - Stiller, Barbara
AU - Arias, Esperanza
AU - Ahmad, Atta
AU - Rauch, Jennifer N.
AU - Chatterjee, Victor
AU - Melis, Chiara
AU - Scharf, Brian
AU - Gestwicki, Jason E.
AU - Cuervo, Ana Maria
AU - Zuiderweg, Erik R.P.
AU - Santambrogio, Laura
N1 - Funding Information:
This work was supported by National Institutes of Health Grants AG045223 (to LS.), AG031782 (to A. M.C. and LS.), NS059690 (to E. R. P.Z. and J. E.G.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
PY - 2016/8/26
Y1 - 2016/8/26
N2 - hsc-70 (HSPA8) is a cytosolic molecular chaperone, which plays a central role in cellular proteostasis, including quality control during protein refolding and regulation of protein degradation. hsc-70 is pivotal to the process of macroautophagy, chaperone-mediated autophagy, and endosomal microautophagy. The latter requires hsc-70 interaction with negatively charged phosphatidylserine (PS) at the endosomal limiting membrane. Herein, by combining plasmon resonance, NMR spectroscopy, and amino acid mutagenesis, we mapped the C terminus of the hsc-70 LID domain as the structural interface interacting with endosomal PS, and we estimated an hsc-70/PS equilibrium dissociation constant of 4.7 ± 0.1 μm. This interaction is specific and involves a total of 4-5 lysine residues. Plasmon resonance and NMR results were further experimentally validated by hsc-70 endosomal binding experiments and endosomal microautophagy assays. The discovery of this previously unknown contact surface for hsc-70 in this work elucidates the mechanism of hsc-70 PS/membrane interaction for cytosolic cargo internalization into endosomes.
AB - hsc-70 (HSPA8) is a cytosolic molecular chaperone, which plays a central role in cellular proteostasis, including quality control during protein refolding and regulation of protein degradation. hsc-70 is pivotal to the process of macroautophagy, chaperone-mediated autophagy, and endosomal microautophagy. The latter requires hsc-70 interaction with negatively charged phosphatidylserine (PS) at the endosomal limiting membrane. Herein, by combining plasmon resonance, NMR spectroscopy, and amino acid mutagenesis, we mapped the C terminus of the hsc-70 LID domain as the structural interface interacting with endosomal PS, and we estimated an hsc-70/PS equilibrium dissociation constant of 4.7 ± 0.1 μm. This interaction is specific and involves a total of 4-5 lysine residues. Plasmon resonance and NMR results were further experimentally validated by hsc-70 endosomal binding experiments and endosomal microautophagy assays. The discovery of this previously unknown contact surface for hsc-70 in this work elucidates the mechanism of hsc-70 PS/membrane interaction for cytosolic cargo internalization into endosomes.
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U2 - 10.1074/jbc.M116.736744
DO - 10.1074/jbc.M116.736744
M3 - Article
C2 - 27405763
AN - SCOPUS:84984783742
VL - 291
SP - 18096
EP - 18106
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 35
ER -