Researchers from Sweden have published a new molecular mapping of proteins that regulate the cell division process – identifying 300 involved proteins.
The cell cycle is a highly ordered sequence of events that prepares the cell for cellular division. In order for cells to divide, they must progress through a series of checkpoints. These steps are controlled by the presence and activity of specific proteins. The proteins are regulated precisely in time and space by transcriptional regulation, post-translational modification loops and protein degradation.
Studies have shown that several hundred genes and proteins are regulated by the cell cycle. In addition, more recently, single-cell RNA sequencing studies have found additional cell-cycle-dependent (CCD) genes. However, technological limitations have precluded the investigation of variability in single-cell protein expression.
Map of the human cell cycle
In this study, published in Nature, researchers presented a comprehensive, spatiotemporal map of human proteomic heterogeneity. Specifically, the team integrated proteomics at subcellular resolution with single-cell transcriptomics and precise temporal measurements of individual cells in the cell cycle.
Their results showed that around one-fifth of the human proteome displays cell-to-cell variability. The team identified hundreds of proteins with previously unknown associations with mitosis and the cell cycle. They also provided evidence that several of these proteins have oncogenic functions. In addition, they found that most CCD proteins are regulated post-translationally, rather than by transcript cycling. These proteins were also disproportionately phosphorylated by kinases that regulated cell fate.
These results provide a more complete picture of the cell division cycle and proteomic variability between individual human cells. This is important for understanding the molecular underpinnings of biological processes and disease. This spatially resolved map of the cell cycle is now integrated into the Human Protein Atlas. This will serve as an important resource for accelerating molecular studies of the human cell cycle and cell proliferation.
Image credit: By CreVis2 – canva.com