A non-canonical role for pyruvate kinase M2 as a functional modulator of Ca2+ signalling through IP3 receptors

Andrew R. Lavik, Karen S. McColl, Fernanda O. Lemos, Martijn Kerkhofs, Fei Zhong, Michael Harr, Daniela Schlatzer, Kozo Hamada, Katsuhiko Mikoshiba, Francesco Crea, Geert Bultynck, Martin D. Bootman*, Jan B. Parys, Clark W. Distelhorst

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Pyruvate kinase isoform M2 (PKM2) is a rate-limiting glycolytic enzyme that is widely expressed in embryonic tissues. The expression of PKM2 declines in some tissues following embryogenesis, while other pyruvate kinase isozymes are upregulated. However, PKM2 is highly expressed in cancer cells and is believed to play a role in supporting anabolic processes during tumour formation. In this study, PKM2 was identified as an inositol 1,4,5-trisphosphate receptor (IP3R)-interacting protein by mass spectrometry. The PKM2:IP3R interaction was further characterized by pull-down and co-immunoprecipitation assays, which showed that PKM2 interacted with all three IP3R isoforms. Moreover, fluorescence microscopy indicated that both IP3R and PKM2 localized at the endoplasmic reticulum. PKM2 binds to IP3R at a highly conserved 21-amino acid site (corresponding to amino acids 2078–2098 in mouse type 1 IP3R isoform). Synthetic peptides (denoted ‘TAT-D5SD’ and ‘D5SD’), based on the amino acid sequence at this site, disrupted the PKM2:IP3R interaction and potentiated IP3R-mediated Ca2+ release both in intact cells (TAT-D5SD peptide) and in a unidirectional 45Ca2+ flux assay on permeabilized cells (D5SD peptide). The TAT-D5SD peptide did not affect the enzymatic activity of PKM2. Reducing PKM2 protein expression using siRNA increased IP3R-mediated Ca2+ signalling in intact cells without altering the ER Ca2+ content. These data identify PKM2 as an IP3R-interacting protein that inhibits intracellular Ca2+ signalling. The elevated expression of PKM2 in cancer cells is therefore not solely connected to its canonical role in glycolytic metabolism, rather PKM2 also has a novel non-canonical role in regulating intracellular signalling.

Original languageEnglish
Article number119206
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Issue number4
Publication statusPublished - Apr 2022
Externally publishedYes


  • B cells
  • Ca signalling
  • Endoplasmic reticulum
  • IP receptor
  • PKM2
  • T cells


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