Protein Kinase CK2 Subunits Differentially Perturb the Adhesion and Migration of GN11 Cells: A Model of Immature Migrating Neurons.

Antonella Lettieri,Alyssa Paganoni,Claudio D’Amore,Anna Cariboni,Lorenzo A Pinna,Roberto Oleari,Christian Borgo,Luca Zanieri,Mauro Salvi

doi:10.3390/ijms20235951

Abstract

Protein kinase CK2 (CK2) is a highly conserved and ubiquitous kinase is involved in crucial biological processes, including proliferation, migration, and differentiation. CK2 holoenzyme is a tetramer composed by two catalytically active (α/α’) and two regulatory (β) subunits and exerts its function on a broad range of targets. In the brain, it regulates different steps of neurodevelopment, such as neural differentiation, neuritogenesis, and synaptic plasticity. Interestingly, CK2 mutations have been recently linked to neurodevelopmental disorders; however, the functional requirements of the individual CK2 subunits in neurodevelopment have not been yet investigated. Here, we disclose the role of CK2 on the migration and adhesion properties of GN11 cells, an established model of mouse immortalized neurons, by different in vitro experimental approaches. Specifically, the cellular requirement of this kinase has been assessed pharmacologically and genetically by exploiting CK2 inhibitors and by generating subunit-specific CK2 knockout GN11 cells (with a CRISPR/Cas9-based approach). We show that CK2α’ subunit has a primary role in increasing cell adhesion and reducing migration properties of GN11 cells by activating the Akt-GSK3β axis, whereas CK2α subunit is dispensable. Further, the knockout of the CK2β regulatory subunits counteracts cell migration, inducing dramatic alterations in the cytoskeleton not observed in CK2α’ knockout cells. Collectively taken, our data support the view that the individual subunits of CK2 play different roles in cell migration and adhesion properties of GN11 cells, supporting independent roles of the different subunits in these processes.

Highlights

Protein kinase CK2 (CK2) is a master serine–threonine kinase that phosphorylates hundreds of targets [1,2], controlling a wide range of biological cell processes, including proliferation, survival, cell death, differentiation, and migration [3,4,5]
CK2 is a tetrameric Ser/Thr protein kinase that phosphorylates a plethora of different substrates and participates in numerous cellular physiological and pathological processes, such as proliferation, survival, apoptosis, angiogenesis, cancer progression, DNA damage and repair, ER stress response, carbohydrate metabolism, and brain development [5]
Mutations in CSNK2A1 and CSNK2B genes, encoding for α catalytic subunit and β regulatory subunits, respectively, have been found in patients with neurodevelopmental disorders (NDDs) [22,23,24,25,26], but the functional role of CK2 has not been elucidated in these works

Summary

Introduction

Protein kinase CK2 (CK2) is a master serine–threonine kinase that phosphorylates hundreds of targets [1,2], controlling a wide range of biological cell processes, including proliferation, survival, cell death, differentiation, and migration [3,4,5]. Despite such a similarity, both catalytic subunits are active in vitro independent of their association to the β subunits [6]. The phosphorylation of many typical CK2 targets, such as S129-Akt, S13-Cdc, and S529-NF-kBp65, is substantially increased by CK2β [7,8]. This suggests that regulatory subunits control the substrate-specific targeting of catalytic subunits. CSNK2A1 (CK2α) and CSNK2A2 (CK2α’) genes encode for the two catalytic proteins, while CSNK2B (CK2β) encodes for the regulatory β subunit. Very similar in the N-terminal region (90% sequence homology), the two catalytic subunits display C-terminal differences that could account for distinct functions in vivo

Methods

Results

Conclusion