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 - Publisher Copyright:
© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
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
SN - 0021-9258
VL - 291
SP - 18096
EP - 18106
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 35
ER -