Testi M G, Croce R, Polverino-De Laureto P, Bassi R
Università di Verona, Facoltà di Scienze MM.FF.NN., Biotecnologie Vegetali, Verona, Italy.
FEBS Lett. 1996 Dec 16;399(3):245-50. doi: 10.1016/s0014-5793(96)01333-6.
Protein phosphorylation is a major mechanism in the regulation of protein function. In chloroplast thylakoids several photosystem II subunits, including the major antenna light-harvesting complex II and several core complex components, are reversibly phosphorylated depending on the redox state of the electron carriers. A previously unknown reversible phosphorylation event has recently been described on the CP29 subunit which leads to conformational changes and protection from cold stress (Bergantino, E., Dainese, P., Cerovic, Z. Sechi, S. and Bassi, R. (1995) J. Biol Chem. 270, 8474-8481). In this study, we have identified the phosphorylation site on the N-terminal, stroma-exposed domain, showing that it is located in a sequence not homologous to the other members of the Lhc family. The phosphorylated sequence is unique in chloroplast membranes since it meets the requirements for CK2 (casein kinase II) kinases. The possibility that this phosphorylation is involved in a signal transduction pathway is discussed.
蛋白质磷酸化是调节蛋白质功能的主要机制。在叶绿体类囊体中，包括主要天线捕光复合物II和几个核心复合物成分在内的几个光系统II亚基，会根据电子载体的氧化还原状态进行可逆磷酸化。最近在CP29亚基上描述了一种以前未知的可逆磷酸化事件，该事件导致构象变化并抵御冷胁迫（Bergantino, E., Dainese, P., Cerovic, Z. Sechi, S.和Bassi, R. (1995) J. Biol Chem. 270, 8474 - 8481）。在本研究中，我们确定了N端、面向基质区域的磷酸化位点，表明它位于一个与Lhc家族其他成员不同源的序列中。磷酸化序列在叶绿体膜中是独特的，因为它符合酪蛋白激酶II（CK2）激酶的要求。本文讨论了这种磷酸化参与信号转导途径的可能性。
