Biology subjects

Haider, N.

Publications and source records attributed to Haider, N..

5 recordsLinked to original sources

bioRxiv2022

NEK10 tyrosine phosphorylates β-catenin to regulate its cytoplasmic turnover.

Nek kinases are involved in regulating several different elements of the centrosomal cycle, primary cilia function, and DNA damage responses. Unlike the other members of the Nek family, which are serine-threonine kinases, Nek10 preferentially targets tyrosines. Nek10 appears to have a broad role in DNA damage responses, regulating a MAPK-activated G2/M checkpoint following UV irradiation and influencing the p53-mediated activation induced by genotoxicity. In an attempt to identify additional Nek10 functions, we characterized the effect of Nek10 deletion in lung cancer cells, where it is relatively highly expressed. Nek10 absence led to an increase in both the signaling and adherens junctions pools of {beta}-catenin. Mechanistically, Nek10 associates with the Axin complex where it phosphorylates {beta}-catenin at Tyr30, located within the regulatory region governing {beta}-catenin turnover. In the absence of Nek10 phosphorylation, GSK3-mediated phosphorylation of {beta}-catenin, a prerequisite for its turnover, was significantly impaired. Stabilization of {beta}-catenin driven by Nek10 loss diminished the ability of cells to form tumorspheres in suspension, grow in soft agar, and colonize mouse lung tissue following tail vein injections.

cancer biology↗

bioRxiv2019

Dual SMAD inhibition and Wnt inhibition enhances the differentiation of induced pluripotent stem cells into Retinal Ganglion cells (iPSC-RGCs)

Glaucoma is a group of progressive optic neuropathies that share common biological and clinical characteristics including irreversible changes to the optic nerve and visual field loss caused by death of retinal ganglion cells (RGCs). The loss of RGCs manifests as characteristic cupping or optic nerve degeneration, resulting in visual field loss in patients with Glaucoma. Published studies on in vitro RGC differentiation from stem cells utilized classical RGC signaling pathways mimicking retinal development in vivo. Although many strategies allowed for the generation of RGCs, increased variability between experiments and lower yield hampered the cross comparison between individual lines and between experiments. To address this critical need, we developed a reproducible chemically defined in vitro methodology for generating retinal progenitor cell (RPC) populations from iPSCs, that are efficiently directed towards RGC lineage. Using this method, we reproducibly differentiated iPSCs into RGCs with greater than 80% purity, without any genetic modifications. We used small molecules and peptide modulators to inhibit BMP, TGF-{beta} (SMAD), and canonical Wnt pathways that reduced variability between iPSC lines and yielded functional and mature iPSC-RGCs. Using CD90.2 antibody and Magnetic Activated Cell Sorter (MACS) technique, we successfully purified Thy-1 positive RGCs with nearly 95% purity.

neuroscience↗

bioRxiv2019

NEK10 tyrosine phosphorylates p53 and controls its transcriptional activity

In response to genotoxic stress, multiple kinase signalling cascades are activated, many of them directed towards the tumour suppressor p53 which coordinates the DNA damage response (DDR). Defects in DDR pathways lead to an accumulation of mutations that can promote tumorigenesis. Emerging evidence implicates multiple members of the NimA-related kinase (NEK) family (NEK1, NEK10 and NEK11) in the DDR. Here, we describe a function for NEK10 in the regulation of p53 transcriptional activity through tyrosine phosphorylation. NEK10 loss increases cellular proliferation through modulation of the p53-dependent transcriptional output, by directly phosphorylating p53 on Y327, revealing NEK10s unexpected substrate specificity. A p53 mutant at this site (Y327F) acts as a hypomorph, causing an attenuated p53-mediated transcriptional response. Consistently, NEK10-deficient cells display heightened sensitivity to DNA damaging agents and low NEK10 expression is an independent predictor of a favorable response to radiation treatment in WT TP53 breast cancer patients.

cancer biology↗

bioRxiv2019

Comprehensive substrate specificity profiling of the human nek kinome reveals unexpected signaling outputs

Human NimA-related kinases (Neks) have multiple mitotic and non-mitotic functions, but few substrates are known. We systematically determined the phosphorylation-site motifs for the entire Nek kinase family, except for Nek11. While all Nek kinases strongly select for hydrophobic residues in the -3 position, the family separates into four distinct groups based on specificity for a serine versus threonine phospho-acceptor, and preference for basic or acidic residues in other positions. Unlike Nek1-Nek9, Nek10 is a dual-specificity kinase that efficiently phosphorylates itself and peptide substrates on serine and tyrosine, and its activity is enhanced by tyrosine auto-phosphorylation. Nek10 dual-specificity depends on residues in the HRD+2 and APE-4 positions that are uncommon in either serine/threonine or tyrosine kinases. Finally, we show that the phosphorylation-site motifs for the mitotic kinases Nek6, Nek7 and Nek9 are essentially identical to that of their upstream activator Plk1, suggesting that Nek6/7/9 function as phospho-motif amplifiers of Plk1 signaling.

biochemistry↗

bioRxiv2017

Complete Transcriptome Profiling Of Normal And Age-Related Macular Degeneration Eye Tissues Reveals Changes In Regulation Of Non-Coding RNA And Extreme Disregulation Of Anti-Sense Transcription

Strand specific RNA sequencing of retina and RPE-Choroid-Scleara (RCS) in age-related macular degeneration (AMD) and matched normal controls reveals striking impact on anti-sense transcription and changes in the regulation of non-coding RNA that has not previously been reported. Hundreds of genes, which do not express anti-sense transcripts in normal retina and RCS, demonstrate extreme anti-sense expression in AMD. And conversely anti-sense transcription is completely abrogated in many genes which express a high level of anti-sense transcripts in normal retina and RCS. Several pathways are very highly enriched in the upregulated anti-sense transcripts - in particular the EIF2 signaling pathway. These results call for a deeper investigation into anti-sense and noncoding RNA regulation in AMD and their potential as therapeutic targets.

genomics↗