Weigmann A, Corbeil D, Hellwig A, Huttner W B
Department of Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120, Heidelberg, Germany.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12425-30. doi: 10.1073/pnas.94.23.12425.
Using a new mAb raised against the mouse neuroepithelium, we have identified and cDNA-cloned prominin, an 858-amino acid-containing, 115-kDa glycoprotein. Prominin is a novel plasma membrane protein with an N-terminal extracellular domain, five transmembrane segments flanking two short cytoplasmic loops and two large glycosylated extracellular domains, and a cytoplasmic C-terminal domain. DNA sequences from Caenorhabditis elegans predict the existence of a protein with the same features, suggesting that prominin is conserved between vertebrates and invertebrates. Prominin is found not only in the neuroepithelium but also in various other epithelia of the mouse embryo. In the adult mouse, prominin has been detected in the brain ependymal layer, and in kidney tubules. In these epithelia, prominin is specific to the apical surface, where it is selectively associated with microvilli and microvilli-related structures. Remarkably, upon expression in CHO cells, prominin is preferentially localized to plasma membrane protrusions such as filopodia, lamellipodia, and microspikes. These observations imply that prominin contains information to be targeted to, and/or retained in, plasma membrane protrusions rather than the planar cell surface. Moreover, our results show that the mechanisms underlying targeting of membrane proteins to microvilli of epithelial cells and to plasma membrane protrusions of non-epithelial cells are highly related.
利用一种针对小鼠神经上皮产生的新型单克隆抗体，我们鉴定并通过cDNA克隆了prominin，它是一种含有858个氨基酸、分子量为115 kDa的糖蛋白。Prominin是一种新型的质膜蛋白，具有N端细胞外结构域、五个跨膜区段，两侧各有两个短的细胞质环和两个大的糖基化细胞外结构域，以及一个细胞质C端结构域。秀丽隐杆线虫的DNA序列预测存在一种具有相同特征的蛋白质，这表明prominin在脊椎动物和无脊椎动物之间是保守的。Prominin不仅存在于神经上皮中，还存在于小鼠胚胎的各种其他上皮中。在成年小鼠中，已在脑室管膜层和肾小管中检测到prominin。在这些上皮中，prominin特异性定位于顶端表面，在那里它选择性地与微绒毛和微绒毛相关结构相关联。值得注意的是，在CHO细胞中表达时，prominin优先定位于质膜突起，如丝状伪足、片状伪足和微刺。这些观察结果表明，prominin包含靶向质膜突起而非平面细胞表面并/或保留在其中的信息。此外，我们的结果表明，膜蛋白靶向上皮细胞微绒毛和非上皮细胞质膜突起的潜在机制高度相关。
