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bioRxiv · 10.1101/2020.03.27.012724

Evidence of Presence and Activation of the two Cell Cycle Kinases Nek6 and Nek7 in the ciliated Neuroretina

Janisch, K. M.·Kasanuki, J. M.·Davis, R. J.·Tsang, S. H.
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Abstract

The serine/threonine NIMA kinases are widely found in eukaryotes. They are cell-cycle kinases that are associated with centrosomes and spindle apparatus and cilia. In cilia, NIMA kinases are reported to play a role in cilia length maintenance and deflagelation. Here we focus on the two Nek homologs, Nek6 and Nek7, and their potential role in retina. We report for the first-time expression of nek6 and nek7 mRNA and protein in retinal tissue. In particular, we detect localisation of these kinases to photoreceptors outer segments. Moreover, we are able to show a light-dependent phosphorylation of the activation loop (serine 206) of Nek6/7 in rod outer segments, suggesting activation of these kinases is downstream of the phototransduction pathway. Indeed, we demonstrate that Nek6/7 phosphorylation in the retina is dependent on Grk1 function. Furthermore, Nek6/7 phosphorylation can be stimulated in the brain by opiate drugs, suggesting that activation of Nek6/7 lies downstream of G protein coupled receptors activation, in general. Nek6/7 may couple photoreception with outer segment biogenesis through phosphorylation of downstream substrates, which may affect the microtubules of the axoneme.

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Janisch, K. M., Kasanuki, J. M., Davis, R. J., Tsang, S. H.. 2020-03-29. Evidence of Presence and Activation of the two Cell Cycle Kinases Nek6 and Nek7 in the ciliated Neuroretina. https://doi.org/10.1101/2020.03.27.012724

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