PRMT3 is a distinct member of the protein arginine N-methyltransferase family -: Conferral of substrate specificity by a zinc-finger domain
PRMT3 is a distinct member of the protein arginine N-methyltransferase family -: Conferral of substrate specificity by a zinc-finger domain
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DOI：
10.1074/jbc.m006445200
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发表时间：
2000-10-20
影响因子：
4.8
通讯作者：
Clarke, S
中科院分区：
文献类型：
--
作者：
Frankel, A;Clarke, S
S-腺苷-L-甲硫氨酸依赖性蛋白质精氨酸N-甲基转移酶（PRMT）催化多种蛋白质中精氨酸残基的甲基化。目前已经描述了至少四种不同的哺乳动物家族成员，包括PRMT 1、PRMT 3、CARM 1/PRMT 4和JBP 1/PRMT 5。为了更全面地定义PRMT 3的生理作用，我们表征了其独特的推定锌指结构域以及它如何影响其酶活性。在这里，我们表明，PRMT 3确实包含一个单一的锌指结构域在其氨基末端。虽然锌配体形式的这个域是不需要的人工底物，如谷胱甘肽S-转移酶-原纤蛋白氨基末端融合蛋白（GST-GAR）的甲基化，它是需要的酶识别RNA相关的底物在RAT 1细胞提取物。PRMT 3的重组形式被高浓度的ZnCl 2以及N-乙基马来酰亚胺抑制，这些试剂可以修饰半胱氨酸巯基。我们发现，我们可以区分PRMT家族成员，他们对这些试剂的敏感性; JBP 1/PRMT 5和HsI 7甲基转移酶的抑制方式与PRMT 3相似，而Rmt 1，PRMT 1和CARM 1/PRMT 4不受影响。我们还能够通过这些酶对Tris和游离精氨酸抑制的敏感性来定义这些酶的差异。最后，我们发现用N-乙基马来酰亚胺处理RAT 1细胞提取物导致主要PRMT 1相关活性的丧失，该活性在与GST融合蛋白相同的条件下对抑制免疫。这些结果表明，原生形式的PRMT可以有不同的属性比他们的GST-催化链融合蛋白的对应物，这可能缺乏相关的非催化亚基。
S-Adenosyl-L-methionine-dependent protein arginine N-methyltransferases (PRMTs) catalyze the methylation of arginine residues within a variety of proteins. At least four distinct mammalian family members have now been described, including PRMT1, PRMT3, CARM1/PRMT4, and JBP1/PRMT5. To more fully define the physiological role of PRMT3, we characterized its unique putative zinc-finger domain and how it can affect its enzymatic activity. Here we show that PRMT3 does contain a single zinc-finger domain in its amino terminus. Although the zinc-liganded form of this domain is not required for methylation of an artificial substrate such as the glutathione S-transferase-fibrillarin amino-terminal fusion protein (GST-GAR), it is required for the enzyme to recognize RNA-associated substrates in RAT1 cell extracts. The recombinant form of PRMT3 is inhibited by high concentrations of ZnCl2 as well as N-ethylmaleimide, reagents that can modify cysteine sulfhydryl groups. We found that we could distinguish PRMT family members by their sensitivity to these reagents; JBP1/PRMT5 and HsI7 methyltransferases were inhibited in a similar manner as PRMT3, whereas Rmt1, PRMT1, and CARM1/PRMT4 were not affected. We were also able to define differences in these enzymes by their sensitivity to inhibition by Tris and free arginine. Finally, we found that the treatment of RAT1 cell extracts with N-ethylmaleimide leads to a loss of the major PRMT1-associated activity that was immune to inhibition under the same conditions as a GST fusion protein. These results suggest that native forms of PRMTs can have different properties than their GST-catalytic chain fusion protein counterparts, which may lack associated noncatalytic subunits.