Localization of the PP2A B56γ regulatory subunit at the Golgi complex -: Possible role in vesicle transport and migration
Localization of the PP2A B56γ regulatory subunit at the Golgi complex -: Possible role in vesicle transport and migration
复制标题
DOI：
10.1016/s0002-9440(10)63842-4
复制
发表时间：
2003-02-01
影响因子：
6
通讯作者：
Kitamura, Y
中科院分区：
文献类型：
--
作者：
Ito, A;Koma, YI;Kitamura, Y
BL6亚系来源于F10系，F10系来源于B16小鼠黑素瘤细胞系。BL6细胞比F10细胞更具侵袭性，并且通过改变编码蛋白磷酸酶2A（PP2A）的B56 γ调节亚基的基因而与F10细胞遗传上不同。这种改变导致编码B56 γ 1同种型（Deltagamma1）的截短变体的mRNA的转录。当F10细胞用识别三种B56 γ同种型B56 γ 1、B56 γ 2和B56 γ 3的多克隆抗体染色时，免疫荧光信号与顺式高尔基体标记蛋白共定位良好。当BL6细胞在蔗糖梯度中分级分离时，B56 γ 1和B56 γ 2，而不是B56 γ 3，存在于高尔基体富集的组分中。该级分还含有PP2A的催化亚基。FLAG标记的Deltagamma1优先定位于反式高尔基体区域，而不是顺式高尔基体。这种定位与FLAG标记的B56 γ 1相同。稳定表达Deltagamma1的NIH3T3细胞从内质网转运突变病毒蛋白。比野生型细胞快得多。它们的定向迁移，如通过细胞进入无细胞区域的进展所评估的，也升高了。由于Deltagamma1降低了含有B56 γ的PP2A全酶的活性，这些结果表明，正常的全酶抑制囊泡运输，Deltagamma1可能通过激活高尔基体功能增加BL6细胞的侵袭能力。
The BL6 subline was derived from the F10 line, which was derived from the B16 mouse melanoma cell line. BL6 cells are more invasive than F10 cells and differ genetically from F10 cells by an alteration of the gene encoding the B56gamma regulatory subunit of protein phosphatase 2A (PP2A). This alteration results in the transcription of mRNA encoding a truncated variant of the B56gamma1 isoform (Deltagamma1). When F10 cells were stained with a polyclonal antibody that recognizes three B56gamma isoforms, B56gamma1, B56gamma2, and B56gamma3, the immunofluorescent signals co-localized well with the cis-Golgi marker proteins. When BL6 cells were fractionated in a sucrose gradient, B56gamma1 and B56gamma2, but not B56gamma3, were present in the Golgi-enriched fraction. This fraction also contained the catalytic subunit of PP2A. FLAG-tagged Deltagamma1 preferentially localized to the trans-Golgi area rather than the cis-Golgi. This localization was the same as that of FLAG-tagged B56gamma1. NIH3T3 cells stably expressing Deltagamma1 transported a mutant viral protein from the endoplasmic reticulum. to the plasma membrane much faster than wild-type cells. Their directional migration, as assessed by the advance of cells into a cell-free area, was also elevated. As Deltagamma1 reduces the activity of the B56gamma-containing PP2A holoenzymes, these results suggest that the normal holoenzymes suppress vesicle transport and that Deltagamma1 might increase the invasive ability of BL6 cells by activating Golgi function.