FIR haplodeficiency promotes splicing to pyruvate kinase M2 in mice thymic lymphoma tissues revealed by six-plex tandem mass tag quantitative proteomic analysis
ONCOTARGET
Authors: Kimura, Asako; Kitamura, Kouichi; Ailiken, Guzhanuer; Satoh, Mamoru; Minamoto, Toshinari; Tanaka, Nobuko; Nomura, Fumio; Matsushita, Kazuyuki
Abstract
The switch of pyruvate kinase (PK) M1 to PKM2 is pivotal for glucose metabolism in cancers. The PKM1/M2 shift is controlled by the alternative splicing of two mutually exclusive exons in the PKM gene. PKM1 is expressed in differentiated tissues, whereas PKM2 is expressed in cancer tissues. This study revealed that the haplodeficiency of FUSE-binding protein (FBP)-interacting repressor (FIR), a transcriptional repressor of the c-myc gene, contributed to the splicing of PKM1 to PKM2 in mice thymic lymphoma and/or T-cell type acute lymphoblastic leukemia (T-ALL) using six-plex tandem mass tag (TMT) quantitative proteomic analysis. TMT revealed 648 proteins that were up-or downregulated in mice thymic lymphoma tissues compared with wild type mouse. These proteins included transcription factors and proteins involved in DNA damage repair, DNA replication, T-cell activation/proliferation, apoptosis, etc. Among them, PKM2 protein, but not PKM1, was upregulated in the thymic lymphoma as well as T-ALL. Using qRT-PCR, we revealed that the activation of PKM2 mRNA was higher in thymic lymphoma cells of FIR(+/-)TP53(-/-) mice than that in control lymphocytes of FIR(+/+)TP53(-/-) sorted by flow cytometry. FIR knockdown by siRNA suppressed hnRNPA1 expression in HeLa cells. These results indicated that FIR haplodeficiency contributes the alternative splicing of PKM1 to PKM2 by partly inhibiting hnRNPA1 expression in the thymic lymphoma cells prior to T-ALL. Taken together, our findings suggest that FIR and its related spliceosomes are potential therapeutic targets for cancers, including T-ALL.
PKM-zeta Expression Is Important in Consolidation of Memory in Prelimbic Cortex Formed by the Process of Behavioral Tagging
NEUROSCIENCE
Authors: Naseem, Mehar; Tabassum, Heena; Parvez, Suhel
Abstract
Memories are acquired and stored in two forms, short-term memory (STM) and long-term memory (LTM). For the consolidation of LTM, de novo protein synthesis is required, which are also known as plasticity related proteins. Long-term potentiation is a form of synaptic plasticity and it is considered as a cellular model of learning and memory. One of the Longterm potentiation specific plasticity related proteins, PKM-zeta, is required for the formation of LTM as well as for the maintenance of Long-term potentiation. In our study, we have shown that for the consolidation of LTM, in addition to Long-term potentiation-specific plasticity related proteins, synaptic tags are required to interact with each other. In the present study, we investigated the involvement of Long-termpotentiation-specific PKM-zeta and learning tags within a critical time window, which are required for the formation of LTM without affecting STM. Behavioral tagging is an established model for the assessment of some forms of learning and memory. Despite being studied for LTM formation for many years, no studies so far have investigated the role of PKM-zeta in Behavioral tagging model. Hence, by using these two different memories based tasks (i.e., Inhibitory avoidance and Novel object recognition tasks), we observed how PKM-zeta activated by exposing a novel arena after a weak training and led to the consolidation of memory. These findings thus show how the process of behavioral tagging activates Long-term potentiation-specific PKM-zeta for the formation of LTM. (C) 2019 IBRO. Published by Elsevier Ltd. All rights reserved.