Defining the Akt1 interactome and its role in regulating the cell cycle

Abstract

Cell growth and proliferation are two diverse processes yet always linked. Akt1, a serine/threonine kinase, is a multi-functional protein implicated in regulation of cell growth, survival and proliferation. Though it has a role in G1/S progression, the manner by which Akt1 controls cell cycle and blends cell growth with proliferation is not well explored. In this study, we characterize the Akt1 interactome as the cell cycle progresses from G0 to G1/S and G2 phase. For this, Akt1-overexpressing HEK293 cells were subjected to AP-MS. To distinguish between individual cell cycle stages, cells were cultured in the light, medium and heavy labelled SILAC media. We obtained 213 interacting partners of Akt1 from these studies. GO classification revealed that a significant number of proteins fall into functional classes related to cell growth or cell cycle processes. Of these, 32 proteins showed varying association with Akt1 in different cell cycle stages. Further analyses uncovered a subset of proteins showing counteracting effects so as to tune stage-specific progression through the cycle. Thus, our study provides some novel perspectives on Akt1-mediated regulation of the cell cycle and offers the framework for a detailed resolution of the downstream cellular mechanisms that are mediated by this kinase.

Single-Cell RNA Sequencing of Human Embryonic Stem Cell Differentiation Delineates Adverse Effects of Nicotine on Embryonic Development

“…A possible mechanism is that nicotine activates RAS/MAPK pathway via nicotinic acetylcholine receptors (nAChRs) to trigger a network that positively regulates cell-cycle progression through G1 to S, such as cyclin D (Hong et al., 2017). Here, although no expression difference was observed on cyclin D and RAS/MAPK in our scRNA-seq data, we found that the components of cell-cycle machinery, such as HSP90AA1 , TUBB4B , and TUBA1B , which are related to G2M transition (Duggal et al., 2018), and HNRNPH1 and HNRNPA2B1 , which are related to G1 to S transition (Duggal et al., 2018), are upregulated in nicotine-exposed muscle cell cluster 3.…”

Transcriptome and Differential Methylation Integration Analysis Identified Important Differential Methylation Annotation Genes and Functional Epigenetic Modules Related to Vitiligo

“…Futhermore, the PPI network showed that CDK1, HSP90AA1, AKT1, BCL2L1, HDAC2, HELLS, and KIF23 are 7 central genes identified by the top 10 high hub nodes after gene overlap. Among these central genes, CDK1 is a set of Ser/Thr kinase system corresponding to cell cycle progression ( 35 ), and its differential expression was found in another vitiligo study ( 36 ); HSP90AA1 plays a key role in signal transduction, protein folding, protein degradation, and morphological evolution ( 37 ); AKT1 and BCL2L1 are involved in apoptosis ( 38 , 39 ), and AKT methylation has been shown to promote skin tumors ( 40 ); HDAC2 interferes with histone deacetylase function ( 41 ); KIF23 plays an important role in the changes of cellular motor cytoskeleton ( 42 ); HELLS is considered to be a regulator of cell senescence and is necessary for DNMT1-mediated methylation maintenance and DNMT3A/DNMT3B-mediated remethylation ( 43 ). Therefore, we speculate that these hub genes may be involved in the pathological process in the early stage of melanocyte loss in vitiligo, but further functional experiments are needed to further explore.…”

Cell Cycle Regulation by Ca2+-Activated K+ (BK) Channels Modulators in SH-SY5Y Neuroblastoma Cells

“…The increase of the intracellular Ca 2+ ions activate phosphatase such as pleckstrin homology domain leucine-rich repeat protein phosphatase PHLPP that specifically dephosphorylate AKT-1 on Ser473 and with less extended protein phosphatases PP2A that may also dephosphorylate AKT-1 at Ser473 [ 57 ]. The cytosolic AKT-1 dephosphorylation is per se responsible for G2 phases accumulation [ 58 ]. The nuclear AKT-1 dephosphorylation can be responsible for G1 phases accumulation induced by PAX following interaction with the nuclear membrane BK channel and a reduction of the nuclear membrane area as observed in our experiments.…”