該基因編碼一種細胞周期蛋白依賴激酶抑制劑，與CDK抑制劑CDKN1A/P21具有有限的相似性。編碼蛋白結合并阻止細胞周期蛋白E-CDK2或細胞周期蛋白D-CDK4復合物的激活，從而控制細胞周期在G1的進展。這種蛋白的降解是由其依賴于CDK的磷酸化和隨后由scf復合物泛素化引起的，是細胞從靜止狀態向增殖狀態過渡所必需的。該基因突變與多發性內分泌腫瘤IV型（MEN4）有關。
This gene encodes a cyclin-dependent kinase inhibitor, which shares a limited similarity with CDK inhibitor CDKN1A/p21. The encoded protein binds to and prevents the activation of cyclin E-CDK2 or cyclin D-CDK4 complexes, and thus controls the cell cycle progression at G1. The degradation of this protein, which is triggered by its CDK dependent phosphorylation and subsequent ubiquitination by SCF complexes, is required for the cellular transition from quiescence to the proliferative state. Mutations in this gene are associated with multiple endocrine neoplasia type IV (MEN4).