The hypophyseal pars tuberalis is enriched with distinct phosphotyrosine-containing proteins not detected in other areas of the brain and pituitary.
The hypophyseal pars tuberalis is enriched with distinct phosphotyrosine-containing proteins not detected in other areas of the brain and pituitary.
复制标题
垂体结节部富含独特的含磷酸酪氨酸的蛋白质，而这些蛋白质在大脑和垂体的其他区域中未检测到。
DOI：
10.1007/bf00318556
复制
发表时间：
1993
影响因子：
3.6
通讯作者：
Livingston,JN
中科院分区：
文献类型：
--
作者：
Unger,JW;Moss,AM;Livingston,JN
许多生长因子受体和原癌基因产物对细胞活性、生长和代谢的调节涉及酪氨酸激酶活性，导致受体的自磷酸化和含磷酸化酪氨酸的蛋白质底物的产生。含磷酸酪氨酸（PY）蛋白的鉴定和精确定位是阐明酪氨酸激酶在中枢神经系统及相关区域调节中的功能作用的第一步。在本报告中，我们描述了PY-含有蛋白质的正中隆起和相邻部结节的大鼠腺垂体免疫细胞化学，光镜和电镜，并通过Western印迹分析。PY-免疫反应被认为是最强烈的整个细胞质的上皮结节部细胞的人口。聚丙烯酰胺凝胶电泳和蛋白质印迹法的组织提取物从不同的大脑和垂体区域证明了一个一般模式的4个主要带的PY-蛋白质，与一个额外的密集带代表一个44 kDa的蛋白质是高度磷酸化的酪氨酸，这是专门发现在结节部。对胰岛素受体（一种以前与PY蛋白分布相关的酪氨酸激酶）存在的进一步研究表明，受体定位于正中隆起外部和内部区域的轴突和神经末梢中。然而，大量的不同的PY-蛋白质存在于结节部的分泌细胞群不能归因于胰岛素受体。我们的研究结果表明，有大量的细胞特异性酪氨酸激酶活性的正中隆起和接触结节，这些可能发挥重要作用的生物信号转导或代谢调节的神经内分泌区域。
The regulation of cell activity, growth and metabolism by a number of growth factor receptors and proto-oncogene products involves tyrosine kinase activity resulting in autophosphorylation of the receptors and production of phosphorylated tyrosine-containing protein substrates. The identification and precise localization of phosphotyrosine (PY)-containing proteins are first steps in elucidating the functional role of tyrosine kinases in the modulation of the central nervous system and related areas. In the present report, we describe PY-containing proteins in the median eminence and adjacent pars tuberalis of the rat adenohypophysis by immunocytochemistry using light and electron microscopy, and by Western blotting analysis. PY-immunoreactivity was found to be most intense throughout the cytoplasm of a population of epithelial pars tuberalis cells. Polyacrylamide gel electrophoresis and Western blotting of tissue extracts from various brain and pituitary regions demonstrated a general pattern of 4 major bands of PY-proteins, with an additional dense band representing a 44 kDa protein that was highly phosphorylated on tyrosines and that was exclusively found in the pars tuberalis. Additional investigation for the presence of insulin receptors, a tyrosine kinase previously correlated with the distribution of PY-proteins, demonstrated a receptor localization in axons and nerve terminals in the external and internal zone of the median eminence. However, the large amount of different PY-proteins present in the secretory cell population of the pars tuberalis could not be attributed to the insulin receptor. Our findings demonstrate that there is a large amount of cell-specific tyrosine kinase activity in the median eminence and contacting the pars tuberalis; these may play a significant role for transduction of biological signals or metabolic regulation in the neuroendocrine region.