Differential effects of polyamines on the phosphorylation of chromatin-associated proteins.
Differential effects of polyamines on the phosphorylation of chromatin-associated proteins.
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多胺对染色质相关蛋白磷酸化的不同影响。
DOI：
10.1042/bj2090197
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Goueli,SA
中科院分区：
文献类型：
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作者：
Ahmed,K;Davis,AT;Goueli,SA
研究染色质相关磷蛋白的磷酸化的性质是由多胺的影响。用~（32）P标记后，染色质相关蛋白被分离成四个组分。组分I包括中性和碱性非组蛋白磷蛋白，包括高迁移率组非组蛋白;组分II主要由组蛋白组成;组分III由一类（盐溶性）酸性非组蛋白磷蛋白组成;组分IV由残余（盐不溶性）酸性非组蛋白磷蛋白组成。肝脏和前列腺的蛋白质在四个组分（I-IV）中的平均相对分布约为1：4：2：1。然而，组织依赖性的差异，观察到32 P在各种蛋白质组分的掺入。在存在多胺（例如1 mM-精胺或2 mM-亚精胺）的情况下，在组分I的非组蛋白蛋白中观察到磷酸化的最大刺激（160-180%），随后是组分III的非组蛋白蛋白（80-110%）。残余的非组蛋白的磷酸化在馏分IV中，和组蛋白的磷酸化在馏分II的小范围内，保持不变的存在下，多胺。因此，多胺并不刺激所有非组蛋白的磷酸化;它们的刺激作用在中性和碱性非组蛋白和一类盐溶性酸性非组蛋白的磷酸化中最为突出。与我们的假设雅阁，多胺对内源性非组蛋白磷酸化的这些差异效应可能与这些底物的构象有关，而不是与内源性激酶有关。
Studies are presented on the nature of chromatin-associated phosphoproteins whose phosphorylation is influenced by polyamines. After labelling with 32P, chromatin-associated proteins were separated into four fractions. Fraction I comprised neutral and basic non-histone phosphoproteins, including high-mobility-group non-histones; fraction II consisted mostly of histones; fraction III consisted of a class of (salt-soluble) acidic non-histone phosphoproteins; and fraction IV consisted of residual (salt-insoluble) acidic non-histone phosphoproteins. The average relative distribution of protein in the four fractions (I-IV) was about 1:4:2:1 for both liver and prostate. However, tissue-dependent differences were observed in the incorporation of 32P in various protein fractions. In the presence of polyamines (e.g. 1 mM-spermine or 2 mM-spermidine) maximal stimulation of phosphorylation was observed in non-histone proteins of fraction I (160-180%), followed by that in non-histone proteins of fraction III (80-110%). The phosphorylation of residual non-histone proteins in fraction IV, and the small extent of phosphorylation of histones in fraction II, remained unaltered in the presence of polyamines. Thus polyamines do not stimulate the phosphorylation of all non-histone proteins; their stimulative effect is most prominent in the phosphorylation of neutral and basic non-histone proteins and a class of salt-soluble acidic non-histone proteins. In accord with our hypothesis, these differential effects of polyamines on phosphorylation of endogenous non-histone proteins may relate to the conformation of these substrates rather than to endogenous kinases.