Department of Hematology and Transfusion Medicine, BioMedical Center, Lund University, 221 84 Lund, Sweden.
Exp Cell Res. 2010 Feb 15;316(4):568-79. doi: 10.1016/j.yexcr.2009.12.007. Epub 2009 Dec 16.
TRIM22 (Staf50), a member of the TRIM protein family, is an interferon (IFN)-inducible protein as well as a p53 target gene. The function of TRIM22 is largely unknown, but TRIM22 is suggested to play a role in viral defense by restriction of viral replication. In addition, TRIM22 may function as a ubiquitin E3 ligase. In contrast to previous reports showing solely cytoplasmic localization of exogenous TRIM22, we report here that endogenous TRIM22 is localized to both nucleus and cytosol in primary human mononuclear cells, as well as in the human osteosarcoma cell line U2OS. Moreover, we demonstrate a colocalization of TRIM22 with the centrosomes in primary cells as well as in U2OS cells, and show that this colocalization is independent of cell cycle phase. Additionally, our data suggest the colocalization with centrosomes to be independent on the microtubule network. Given that some viral protein assembly takes place in the close vicinity of the centrosome, our data suggest that important functions of TRIM22 such as regulation of viral replication and protein degradation may take place in the centrosome. However, further studies are warranted to certify this notion.
TRIM22（Staf50）是 TRIM 蛋白家族的成员，是一种干扰素（IFN）诱导蛋白，也是 p53 的靶基因。TRIM22 的功能在很大程度上尚不清楚，但 TRIM22 被认为通过限制病毒复制在病毒防御中发挥作用。此外，TRIM22 可能作为泛素 E3 连接酶发挥作用。与先前仅报道外源性 TRIM22 主要定位于细胞质的报道相反，我们在此报告内源性 TRIM22 主要定位于人原代单核细胞的细胞核和细胞质中，以及人骨肉瘤细胞系 U2OS 中。此外，我们证明了 TRIM22 在原代细胞和 U2OS 细胞中与中心体的共定位，并且表明这种共定位不依赖于细胞周期阶段。此外，我们的数据表明与中心体的共定位不依赖于微管网络。鉴于一些病毒蛋白组装发生在中心体的附近，我们的数据表明，TRIM22 的重要功能，如调节病毒复制和蛋白降解，可能发生在中心体中。然而，需要进一步的研究来证实这一观点。
