Quantitative proteomics reveals arsenic attenuates stem‐loop binding protein stability via a chaperone complex containing heat shock proteins and ERp44

Abstract

Arsenic pollution impacts health of millions of people in the world. Inorganic arsenic is a carcinogenic agent in skin and lung cancers. The stem‐loop binding protein (SLBP) binds to the stem‐loop of the canonical histone mRNA and regulates its metabolism during cell cycle. Our previous work has shown arsenic induces ubiquitin‐proteasome dependent degradation of SLBP and contributes to lung cancer. In this study, we established the first comprehensive SLBP interaction network by affinity purification‐mass spectrometry (AP‐MS) analysis, and further demonstrated arsenic enhanced the association between SLBP and a crucial chaperone complex containing heat shock proteins (HSPs) and ERp44. Strikingly, knockdown of these proteins markedly rescued the protein level of SLBP under arsenic exposure conditions, and abolished the increasing migration capacity of BEAS‐2B cells induced by arsenic. Taken together, our study provides a potential new mechanism that a chaperone complex containing HSPs and ERp44 attenuates the stability of SLBP under both normal and arsenic exposure conditions, which could be essential for arsenic‐induced high cell migration.

Quantitative Proteomics Reveals Down-Regulated Glycolysis/Gluconeogenesis in the Large-Duct Type Intrahepatic Cholangiocarcinoma

“…Whole-cell lysates were extracted as previously described. 15 HuH28 and RBE cell pellets were lysed in lysis buffer (50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 0.25% sodium deoxycholate, 0.5% NP-40, 1 mM EDTA and 1% Protease Inhibitor Cocktail III and V, 1 mM PMSF, 1 mM NaVO 3 , 1 mM NaF). The suspended lysates were placed on ice for 20 min and centrifuged at 12 000 rpm for 15 min at 4 °C to collect the supernatant.…”