Alternate AChE-R variants facilitate cellular metabolic activity and resistance to genotoxic stress through enolase and RACK1 interactions

Inbal Mor, Tal Bruck, David Greenberg, Amit Berson, Leticia Schreiber, Dan Grisaru, Hermona Soreq

Research output: Contribution to journalArticlepeer-review

Abstract

Tumorogenic transformation is a multifaceted cellular process involving combinatorial protein-protein interactions that modulate different cellular functions. Here, we report apparent involvement in two independent tumorogenic processes by distinct partner protein interactions of the stress-induced acetylcholinesterase AChE-R and N-AChE-R variants. Human testicular tumors showed elevated levels of N-terminally extended N-AChE-R compared with healthy tissue, indicating alternate promoter usage in the transformed cells. Two-hybrid screens demonstrate that the C-terminus common to both N-AChE-R and AChE-R interacts either with the glycolytic enzyme enolase or with the scaffold protein RACK1. In vitro, the AChE-R C-terminal peptide ARP elevated enolase's activity by 12%, suggesting physiological relevance for this interaction. Correspondingly, CHO cells expressing either human AChE-R or N-AChE-R but not AChE-S showed a 25% increase in cellular ATP levels, indicating metabolic significance for this upregulation of enolase activity. ATP levels could be reduced by AChE-targeted siRNA in CHO cells expressing AChE-R but not AChE-S, attributing this elevation to the AChE-R C-terminus. Additionally, transfected CHO cells expressing AChE-R but not N-AChE-R showed resistance to up to 60 μM of the common chemotherapeutic agent, cis-platinum, indicating AChE-R involvement in another molecular pathway. cis-Platinum elevates the expression of the apoptosis-regulator p53-like protein, p73, which is inactivated by interaction with the scaffold protein RACK1. In co-transfected cells, AChE-R competed with endogenous RACK1 for p73 interaction. Moreover, AChE-R-transfected CHO cells presented higher levels than control cells of the pro-apoptotic TAp73 as well as the anti-apoptotic dominant negative ΔNp73 protein, leading to an overall decrease in the proportion of pro-apoptotic p73. Together, these findings are compatible with the hypothesis that in cancer cells, both AChE-R and N-AChE-R elevate cellular ATP levels and that AChE-R modifies p73 gene expression by facilitating two independent cellular pathways, thus conferring both a selective metabolic advantage and a genotoxic resistance.

Original languageEnglish
Pages (from-to)11-21
Number of pages11
JournalChemico-Biological Interactions
Volume175
Issue number1-3
DOIs
StatePublished - 25 Sep 2008
Externally publishedYes

Keywords

  • ATP
  • Acetylcholinesterase
  • Enolase
  • Glycolysis
  • RACK1
  • p73

Fingerprint

Dive into the research topics of 'Alternate AChE-R variants facilitate cellular metabolic activity and resistance to genotoxic stress through enolase and RACK1 interactions'. Together they form a unique fingerprint.

Cite this