What does a tumor suppressor protein primarily do?

A tumor suppressor protein primarily regulates the cell cycle by acting as a checkpoint that inhibits cell division under certain conditions. These proteins are crucial for maintaining normal cellular function and preventing unchecked cell proliferation, which can lead to cancer. They help to ensure that cells do not progress through the cell cycle inappropriately, such as when there is DNA damage or when necessary growth signals are absent. By regulating cell cycle progression, tumor suppressor proteins play an essential role in preserving genomic stability and preventing the development of tumors. This function aligns with the cellular mechanisms that are crucial for maintaining homeostasis and preventing malignancies in tissues.