Fujimoto K, Yasuda H, Sato Y, Yamamoto K
Department of Molecular Pathology, Kanazawa University, Ishikawa, Japan.
Gene. 1995 Nov 20;165(2):183-9. doi: 10.1016/0378-1119(95)00507-3.
A precursor, p105, for one of the subunits (p50) of the NF-kappa B transcription factor, plays an important role in inducible expression of diverse cellular genes. p105 also functions as a cytoplasmic inhibitor for NF-kappa B, and the proteolytic processing of its inhibitory C-terminal region is required for generation of active NF-kappa B. Here, it is reported that the human p105 C-terminal region is phosphorylated in vivo on Ser894 and Ser908, which are potential phosphorylation sites in vitro for proline-directed serine/threonine kinases such as cyclin-dependent kinase. Furthermore, the mutation of these in vivo phosphorylation sites retards p105 processing in vivo, suggesting that p105 processing is regulated in a phosphorylation-dependent manner.
核因子-κB转录因子的一个亚基（p50）的前体p105，在多种细胞基因的诱导性表达中发挥重要作用。p105还作为核因子-κB的细胞质抑制剂发挥作用，其抑制性C末端区域的蛋白水解加工是产生活性核因子-κB所必需的。在此，有报道称人p105的C末端区域在体内的Ser894和Ser908位点发生磷酸化，这两个位点在体外是脯氨酸定向丝氨酸/苏氨酸激酶（如细胞周期蛋白依赖性激酶）的潜在磷酸化位点。此外，这些体内磷酸化位点的突变会延缓p105在体内的加工过程，这表明p105的加工过程是以磷酸化依赖的方式受到调控的。
