Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
Internal regulatory checkpoints ensure that a cell’s size, energy reserves, and DNA quality and completeness are sufficient to advance through the cell cycle. At these checkpoints, positive and negative regulators promote or inhibit a cell’s continuation through the cell cycle. Positive regulators include two protein groups that allow cells to pass through regulatory checkpoints: cyclins and cyclin-dependent kinases (CDKs). These proteins are present in eukaryotes, ranging from yeast to humans. Cyclins can be categorized as G1, G1/S, S, or M cyclins based on the cell cycle phase or transition they are most involved in. Generally, levels of a given cyclin are low during most of the cell cycle but abruptly increase at the checkpoint they most contribute to (G1 cyclins are an exception, as they are required throughout the cell cycle). The cyclin is then degraded by enzymes in the cytoplasm and its levels decline. Meanwhile, cyclins needed for the next checkpoints accumulate. To regulate the cell cycle, cyclins must be bound to a Cyclin-dependent kinase (CDK)—a type of enzyme that attaches a phosphate group to modify the activity of a target protein. …
1School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 2Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 3Department of Obstetrics and Gynecology, School of Medicine, Texas Tech University Health Sciences Center
1Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, 2London Regional Cancer Program, Children's Health Research Institute, and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario
1Department of Cell Biology and Histology, University of the Basque Country, UPV/EHU, 2Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, UPV/EHU, 3Department of Molecular Mechanisms of Disease, University of Zurich
1Molecular and Cellular Biology Department, Beckman Research Institute at the City of Hope, 2Irell & Manella Graduate School of Biological Sciences, 3Department of Molecular Immunology, Beckman Research Institute and the City of Hope