Achen M G, Clauss M, Schnürch H, Risau W
Max-Planck-Institut für physiologische und klinische Forschung, W.G. Kerckhoff-Institut, Abteilung molekulare Zellbiologie, Bad Nauheim, Germany.
Differentiation. 1995 Jul;59(1):15-24. doi: 10.1046/j.1432-0436.1995.5910015.x.
The blood-brain barrier, formed by brain endothelium, is critical for brain function. The development of the blood-brain barrier involves brain angiogenesis and endothelial cell differentiation, processes which require active signal transduction pathways. The differentiation of brain endothelial cells to the "blood-brain-barrier phenotype" involves cytoskeletal changes which modulate the tightness of the barrier. In order to identify signal transduction proteins involved in blood-brain barrier development, cDNA from bovine and murine brain endothelial cells was used in a polymerase chain reaction for cloning of DNA encoding Src homology 3 domains. Src homology 3 domains are structural domains found in many signal transduction proteins. These domains often mediate interaction of signaling proteins with the cytoskeleton and therefore may play a role in the regulation of the cytoskeletal changes which occur during blood-brain-barrier development. Unexpectedly, all bovine and murine clones analyzed from polymerase chain reactions encoded the Src homology 3 domain of one protein, namely the non-receptor tyrosine kinase, Lyn, which is involved in signal transduction in cells of the hemopoietic system. In situ hybridization analyses confirmed the presence of lyn mRNA in developing blood vessels in embryonic and early post-natal mouse brain, but not in endothelium outside the brain. In bovine brain endothelial cells in primary culture, p53lyn is highly abundant and present in two forms which have different patterns of tyrosine phosphorylation. These data suggest that Lyn may be involved in transduction of growth and differentiation signals required for blood-brain-barrier development.
由脑内皮细胞形成的血脑屏障对脑功能至关重要。血脑屏障的发育涉及脑血管生成和内皮细胞分化，这些过程需要活跃的信号转导途径。脑内皮细胞向“血脑屏障表型”的分化涉及细胞骨架变化，这种变化可调节屏障的紧密性。为了鉴定参与血脑屏障发育的信号转导蛋白，牛和鼠脑内皮细胞的cDNA被用于聚合酶链反应，以克隆编码Src同源3结构域的DNA。Src同源3结构域是在许多信号转导蛋白中发现的结构域。这些结构域通常介导信号蛋白与细胞骨架的相互作用，因此可能在调节血脑屏障发育过程中发生的细胞骨架变化中发挥作用。出乎意料的是，从聚合酶链反应分析的所有牛和鼠克隆都编码了一种蛋白质的Src同源3结构域，即非受体酪氨酸激酶Lyn，它参与造血系统细胞中的信号转导。原位杂交分析证实，lyn mRNA在胚胎期和出生后早期小鼠脑发育中的血管中存在，但在脑外的内皮细胞中不存在。在原代培养的牛脑内皮细胞中，p53lyn高度丰富，并以两种具有不同酪氨酸磷酸化模式的形式存在。这些数据表明，Lyn可能参与血脑屏障发育所需的生长和分化信号的转导。
