Phosphorylation of NMDA receptors by cyclin B/CDK1 modulates calcium dynamics and mitosis

Margarita Jacaranda Rosendo-Pineda,Luis Vaca,Linda Wordeman,Arlet Loza-Huerta,Oscar Vivas,Alicia Sampieri,Juan Jesus Vicente,Claudia Moreno,Jonathan Pacheco

doi:10.1038/s42003-020-01393-3

Abstract

N-methyl-D-aspartate receptors (NMDAR) are glutamate-gated calcium channels named after their artificial agonist. NMDAR are implicated in cell proliferation under normal and pathophysiological conditions. However, the role of NMDAR during mitosis has not yet been explored in individual cells. We found that neurotransmitter-evoked calcium entry via endogenous NMDAR in cortical astrocytes was transient during mitosis. The same occurred in HEK293 cells transfected with the NR1/NR2A subunits of NMDAR. This transient calcium entry during mitosis was due to phosphorylation of the first intracellular loop of NMDAR (S584 of NR1 and S580 of NR2A) by cyclin B/CDK1. Expression of phosphomimetic mutants resulted in transient calcium influx and enhanced NMDAR inactivation independent of the cell cycle phase. Phosphomimetic mutants increased entry of calcium in interphase and generated several alterations during mitosis: increased mitotic index, increased number of cells with lagging chromosomes and fragmentation of pericentriolar material. In summary, by controlling cytosolic calcium, NMDAR modulate mitosis and probably cell differentiation/proliferation. Our results suggest that phosphorylation of NMDAR by cyclin B/CDK1 during mitosis is required to preserve mitotic fidelity. Altering the modulation of the NMDAR by cyclin B/CDK1 may conduct to aneuploidy and cancer.

Highlights

N-methyl-D-aspartate receptors (NMDAR) are glutamate-gated calcium channels named after their artificial agonist
The results presented here show the selective phosphorylation of the NMDAR during mitosis by cyclin B/CDK1 complex resulting in the modulation of channel activity to preserve mitotic fidelity
Since astrocytes express several NMDAR subunits, we decided to move to a more controlled environment to study this phenomenon without interference from endogenous subunits, so we expressed NR1 + NR2A subunits in Human embryonic kidney 293 cells (HEK293) cells

Summary

Introduction

N-methyl-D-aspartate receptors (NMDAR) are glutamate-gated calcium channels named after their artificial agonist. The same occurred in HEK293 cells transfected with the NR1/NR2A subunits of NMDAR This transient calcium entry during mitosis was due to phosphorylation of the first intracellular loop of NMDAR (S584 of NR1 and S580 of NR2A) by cyclin B/CDK1. Phosphomimetic mutants increased entry of calcium in interphase and generated several alterations during mitosis: increased mitotic index, increased number of cells with lagging chromosomes and fragmentation of pericentriolar material. If errors occur during chromosome segregation the daughter cells complete mitosis with differing amounts of genetic material and/or variations in chromosome number, a condition called “aneuploidy”[14,15]. Aneuploidy is frequently observed in cancer cells, leading to the hypothesis that errors in mitosis can generate cancerous phenotypes[16,17] For this reason, mitosis in all living organisms is highly regulated to minimize mitotic errors[18,19]. Cyclins bind CDK and form cyclin/CDK complexes that initiate the kinase activity of the CDK, and regulate the transitions between different phases of the cell cycle[20,21]

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