The amino acid sequence of protein II and its phosphorylation site for protein kinase C; the domain structure Ca2+‐modulated lipid binding proteins.
The amino acid sequence of protein II and its phosphorylation site for protein kinase C; the domain structure Ca2+‐modulated lipid binding proteins.
复制标题
蛋白 II 的氨基酸序列及其蛋白激酶 C 的磷酸化位点；Ca2+ 调节的脂质结合蛋白的结构域。
作者：
K. Weber;N. Johnsson;U. Plessmann;P. N. Van;H. Söling;C. Ampe;J. Vandekerckhove
从猪肠上皮中分离的蛋白II是一种Ca2+调节的脂质结合蛋白。本文报道的猪蛋白II的氨基酸序列揭示了一个多基因蛋白家族的特性，该家族包括sarc基因（p36）的酪氨酸激酶底物和EGF受体（p35）。该序列巩固了结构原理，其中可变长度的氨基末端尾部是由四个内部同源片段构建的核心，用于35 - 40 kd范围内的蛋白质。序列数据还表明，该核心现在可以被描述为两个结构域，每个结构域包含一个低同源段和一个高同源段。这一观点解释了两个Ca2+位点，脂质聚集和F -肌动蛋白结合（当存在时），并表明蛋白质II与p36和p35不同的核心特性主要来自片段1和2。蛋白II的蛋白酶敏感尾部非常短，缺乏p36和p35较大尾部结构域中存在的可磷酸化酪氨酸。然而，它像p36结构域一样，是Ca2+和脂质活化蛋白激酶c在体外磷酸化的主要位点。在蛋白II中，这个位点最有可能是苏氨酸6。序列比对也解释了为什么蛋白II不与一个独特的p11相互作用，这可能是p36特有的特性。我们的研究结果进一步表明，肝脏内啡肽可能反映了两种与蛋白质II密切相关的蛋白质。
Protein II isolated from porcine intestinal epithelium is a Ca2+‐modulated lipid‐binding protein. The amino acid sequence of porcine protein II reported here sheds new light on the properties of a multigene protein family which includes the tyrosine kinase substrates of the sarc gene (p36) and of the EGF‐receptor (p35). The sequence consolidates the structural principle in which an amino‐terminal tailpiece of variable length is followed by a core built from four internally homologous segments for those proteins in the 35‐40 kd range. Sequence data also show that the core can now be described as two domains each containing one low and one high homology segment. This view accounts for two Ca2+ sites, lipid aggregation and F‐actin bundling–when present–and suggests that properties of the cores in which protein II differs from p36 and p35 arise primarily from segments 1 and 2. The protease‐sensitive tailpiece of protein II is very short and lacks the phosphorylatable tyrosine present in the larger tail domains of p36 and p35. It harbors, however, like the p36 domain, the major site for in vitro phosphorylation by the Ca2+‐ and lipid‐activated protein kinase C. In protein II this site is most likely threonine 6. The sequence alignment also explains why protein II does not interact with a unique p11, a property probably specific for p36. Our results further suggest that liver endonexin may reflect two protein species both closely related to protein II.