This federal Project Grant award from the National Science Foundation (NSF) Biological Sciences program (CFDA 47.074) supports a research project at Oakland University focused on understanding the role of cell cycle regulators in mature, non-dividing muscle cells. The $502,986 award will fund investigations into how proteins like cyclin-dependent kinase 4 (CDK4) that control cell division and growth may also regulate ribosome biogenesis and muscle cell size in post-mitotic muscle fibers. The project will use novel genetically modified mouse models to manipulate the cell cycle and examine its effects on ribosome production and muscle cell size. Undergraduate students will receive training in muscle biology while contributing to the research. The findings could represent a paradigm shift in understanding the function of cell cycle regulators in terminally differentiated cells. No sub-awards are planned under this grant, which has an ultimate completion date of February 29, 2028.