Department of Biology, Stanford University, Stanford, CA 94305, USA.
Science. 2010 Jul 23;329(5990):436-9. doi: 10.1126/science.1191054. Epub 2010 Jun 17.
In animal cells, the primary cilium transduces extracellular signals through signaling receptors localized in the ciliary membrane, but how these ciliary membrane proteins are retained in the cilium is unknown. We found that ciliary membrane proteins were highly mobile, but their diffusion was impeded at the base of the cilium by a diffusion barrier. Septin 2 (SEPT2), a member of the septin family of guanosine triphosphatases that form a diffusion barrier in budding yeast, localized at the base of the ciliary membrane. SEPT2 depletion resulted in loss of ciliary membrane protein localization and Sonic hedgehog signal transduction, and inhibited ciliogenesis. Thus, SEPT2 is part of a diffusion barrier at the base of the ciliary membrane and is essential for retaining receptor-signaling pathways in the primary cilium.
在动物细胞中，初级纤毛通过定位于纤毛膜的信号受体转导细胞外信号，但这些纤毛膜蛋白如何在纤毛中保留尚不清楚。我们发现，纤毛膜蛋白具有很高的流动性，但它们的扩散在纤毛的基部受到扩散障碍的阻碍。 septin 2（SEPT2）是 GTPase 家族 septin 的一个成员，在出芽酵母中形成扩散障碍，定位于纤毛膜的基部。SEPT2 缺失导致纤毛膜蛋白定位和 Sonic hedgehog 信号转导丢失，并抑制纤毛发生。因此，SEPT2 是纤毛膜基部扩散障碍的一部分，对于将受体信号通路保留在初级纤毛中是必不可少的。
