该基因与肿瘤抑制基因CDKN2A相邻，位于一个在多种肿瘤中经常突变和缺失的区域。该基因编码一种与CDK4或CDK6形成复合物的细胞周期蛋白依赖激酶抑制剂，并阻止CDK激酶的激活，因此编码蛋白作为控制细胞周期G1进展的细胞生长调节剂发挥作用。该基因的表达被发现是由TGF-β显著诱导的，提示其在TGF-β诱导的生长抑制中的作用。该基因的两个选择性剪接转录变体编码不同的蛋白质，已被报道。
This gene lies adjacent to the tumor suppressor gene CDKN2A in a region that is frequently mutated and deleted in a wide variety of tumors. This gene encodes a cyclin-dependent kinase inhibitor, which forms a complex with CDK4 or CDK6, and prevents the activation of the CDK kinases, thus the encoded protein functions as a cell growth regulator that controls cell cycle G1 progression. The expression of this gene was found to be dramatically induced by TGF beta, which suggested its role in the TGF beta induced growth inhibition. Two alternatively spliced transcript variants of this gene, which encode distinct proteins, have been reported.