N-terminal phosphorylation of HP1α increases its nucleosome-binding specificity.
N-terminal phosphorylation of HP1α increases its nucleosome-binding specificity.
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DOI：
10.1093/nar/gku995
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发表时间：
2014-11-10
影响因子：
14.9
通讯作者：
Nakayama J
中科院分区：
文献类型：
--
作者：
Nishibuchi G;Machida S;Osakabe A;Murakoshi H;Hiragami-Hamada K;Nakagawa R;Fischle W;Nishimura Y;Kurumizaka H;Tagami H;Nakayama J
异染色质蛋白1 （HP1）是一种进化上保守的染色体蛋白，与赖氨酸9-甲基化组蛋白H3 （H3K9me）结合，是异染色质的标志。虽然HP1磷酸化已经在一些生物体中被描述，但这种修饰的生物学意义在很大程度上仍然难以捉摸。在这里，我们表明HP1的磷酸化对其核小体结合特性具有关键影响。通过体外磷酸化实验和常规色谱法，我们证明了酪蛋白激酶II （CK2）是主要负责磷酸化人HP1α n端的激酶。体外重组核小体的下拉实验显示，未修饰的HP1α结合的h3k9甲基化核小体和h3k9未甲基化核小体具有相当的亲和力，而ck2磷酸化的HP1α对h3k9me3修饰核小体具有高特异性。电泳迁移率转移实验表明，ck2介导的磷酸化降低了HP1α的内在DNA结合，从而导致其与h3k9me无关的核小体结合。ck2介导的磷酸化对果蝇HP1a和S. pombe sw6的核小体结合特异性有相似的影响。这些结果表明，HP1磷酸化在HP1对h3k9me标记核小体的识别中具有进化保守作用。
Heterochromatin protein 1 (HP1) is an evolutionarily conserved chromosomal protein that binds to lysine 9-methylated histone H3 (H3K9me), a hallmark of heterochromatin. Although HP1 phosphorylation has been described in several organisms, the biological implications of this modification remain largely elusive. Here we show that HP1's phosphorylation has a critical effect on its nucleosome binding properties. By in vitro phosphorylation assays and conventional chromatography, we demonstrated that casein kinase II (CK2) is the kinase primarily responsible for phosphorylating the N-terminus of human HP1α. Pull-down assays using in vitro-reconstituted nucleosomes showed that unmodified HP1α bound H3K9-methylated and H3K9-unmethylated nucleosomes with comparable affinity, whereas CK2-phosphorylated HP1α showed a high specificity for H3K9me3-modified nucleosomes. Electrophoretic mobility shift assays showed that CK2-mediated phosphorylation diminished HP1α's intrinsic DNA binding, which contributed to its H3K9me-independent nucleosome binding. CK2-mediated phosphorylation had a similar effect on the nucleosome-binding specificity of fly HP1a and S. pombe Swi6. These results suggested that HP1 phosphorylation has an evolutionarily conserved role in HP1's recognition of H3K9me-marked nucleosomes.
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影响因子：
16
作者：
Keller, Claudia;Adaixo, Ricardo;Buehler, Marc
通讯作者：
Buehler, Marc
DOI：
10.1083/jcb.200804041
发表时间：
2008-11-17
期刊：
The Journal of cell biology
影响因子：
--
作者：
Aucott R;Bullwinkel J;Yu Y;Shi W;Billur M;Brown JP;Menzel U;Kioussis D;Wang G;Reisert I;Weimer J;Pandita RK;Sharma GG;Pandita TK;Fundele R;Singh PB
通讯作者：
Singh PB
影响因子：
64.8
作者：
Ayoub, Nabieh;Jeyasekharan, Anand D.;Venkitaraman, Ashok R.
通讯作者：
Venkitaraman, Ashok R.
影响因子：
7.7
作者：
Muchardt, C;Guillemé, M;Yaniv, M
通讯作者：
Yaniv, M
影响因子：
5.3
作者：
JAMES, TC;ELGIN, SCR
通讯作者：
ELGIN, SCR