Hastie C J, Cohen P T
Medical Research Council Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK.
FEBS Lett. 1998 Jul 24;431(3):357-61. doi: 10.1016/s0014-5793(98)00775-3.
Protein phosphatase 4 (PP4) is a protein serine/threonine phosphatase that predominantly localises to centrosomes and plays a role in microtubule organisation at centrosomes. Here, PP4 catalytic subunit has been purified from porcine testis to near homogeneity and a specific activity of 680 mU/mg against phosphorylase alpha. The antitumour drug, fostriecin, inhibits PP4 catalytic subunit (IC50 3 nM) with similar potency to PP2A catalytic subunit (IC50 1.5 nM). PP4 is also inhibited in the nanomolar range by several naturally occurring tumour promoters and toxins, with similar IC50 values to those obtained for PP2A. The gene for human PP4 catalytic subunit localises to 16p11.2.
蛋白磷酸酶4（PP4）是一种蛋白丝氨酸/苏氨酸磷酸酶，主要定位于中心体，并在中心体的微管组织中发挥作用。在此，已从猪睾丸中纯化出PP4催化亚基，使其接近均一，并且对磷酸化酶α的比活性为680 mU/mg。抗肿瘤药物福司曲星抑制PP4催化亚基（IC50为3 nM），其效力与PP2A催化亚基（IC50为1.5 nM）相似。几种天然存在的肿瘤启动子和毒素也能在纳摩尔范围内抑制PP4，其IC50值与PP2A的相似。人PP4催化亚基的基因定位于16p11.2。
