A novel nuclear import pathway for the transcription factor TFIIS
A novel nuclear import pathway for the transcription factor TFIIS
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DOI：
10.1083/jcb.143.6.1447
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发表时间：
1998-12-14
影响因子：
7.8
通讯作者：
Blobel, G
中科院分区：
文献类型：
--
作者：
Albertini, M;Pemberton, LF;Blobel, G
我们已经确定了一种新的蛋白质输入到细胞核的途径。我们已经证明了以前鉴定的但未鉴定的酵母蛋白Nmd 5 p具有核转运蛋白的功能，因此将其命名为Kap 119 p（M-r为119 kD的核转运蛋白）。我们将Kap 119 p定位于细胞核和细胞质中，我们确定转录延伸因子TFIIS为其主要同源输入底物。细胞质Kap 119 p与TFIIS以近似化学计量的复合物存在。RanGTP，而不是RanGDP，解离分离的Kap 119 p/TFIIS复合物并结合到Kap 119 p。Kap 119 p也直接结合到一些肽重复含有核孔蛋白在覆盖测定。在野生型细胞中，TFIIS主要定位于细胞核。在KAP 119缺失的菌株中，TFIIS错误定位于细胞质，表明TFIIS通过Kap 119 p输入细胞核。在Kap 119 Delta菌株中，使用其他核转运蛋白介导的输入或输出途径的各种底物的转运不受影响。因此，Kap 119 p是一种新的核转运蛋白，负责转录延伸因子TFIIS的输入。
We have identified a novel pathway for protein import into the nucleus. We have shown that the previously identified but uncharacterized yeast protein Nmd5p functions as a karyopherin, It was therefore designated Kap119p (karyopherin with M-r of 119 kD). We localized Kap119p to both the nucleus and the cytoplasm, We identified the transcription elongation factor TFIIS as its major cognate import substrate. The cytoplasmic Kap119p exists as an approximately stoichiometric complex with TFIIS. RanGTP, not RanGDP, dissociated the isolated Kap119p/TFIIS complex and bound to Kap119p. Kap119p also bound directly to a number of peptide repeat containing nucleoporins in overlay assays. In wild-type cells, TFIIS was primarily localized to the nucleus. In a strain where KAP119 has been deleted, TFIIS was mislocalized to the cytoplasm indicating that TFIIS is imported into the nucleus by Kap119p, The transport of various substrates that use other karyopherin-mediated import or export pathways was not affected in a kap119 Delta strain. Hence Kap119p is a novel karyopherin that is responsible for the import of the transcription elongation factor TFIIS.