Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Dev Cell. 2012 Sep 11;23(3):507-18. doi: 10.1016/j.devcel.2012.07.016. Epub 2012 Aug 23.
Secreted signaling molecules typically float in the outer leaflet of the plasma membrane or freely diffuse away from the signaling cell, suggesting that a signal should be sensed equally by all neighboring cells. However, we demonstrate that Spitz (Spi)-mediated epidermal growth factor receptor (EGFR) signaling is spatially biased to selectively determine the induction of a single bract cell on the proximal side of each mechanosensory organ on the Drosophila leg. Dynamic and oriented cellular protrusions emanating from the socket cell, the source of Spi, robustly favor the Spi/EGFR signaling response in a particular cell among equally competent neighbors. We propose that these protrusive structures enhance signaling by increasing contact between the signaling and responding cells. The planar polarized direction of the protrusions determines the direction of the signaling outcome. This asymmetric cell signaling serves as a developmental mechanism to generate spatially patterned cell fates.
分泌的信号分子通常漂浮在质膜的外叶或从信号细胞自由扩散，这表明信号应该被所有相邻细胞平等地感知。然而，我们证明 Spitz（Spi）介导的表皮生长因子受体（EGFR）信号是空间偏向的，以选择性地确定在果蝇腿上每个机械感受器器官的近端侧诱导单个苞片细胞。源自插座细胞（Spi 的来源）的动态和定向细胞突起，在同样有能力的相邻细胞中，强烈有利于特定细胞中的 Spi/EGFR 信号反应。我们提出，这些突起结构通过增加信号和反应细胞之间的接触来增强信号。突起的平面极化方向决定了信号结果的方向。这种不对称的细胞信号传递是一种产生空间模式化细胞命运的发育机制。
