Kirkham Matthew, Parton Robert G
Institute for Molecular Bioscience, University of Queensland, 4072, Australia.
Biochim Biophys Acta. 2005 Dec 30;1746(3):349-63. doi: 10.1016/j.bbamcr.2005.11.007.
A number of recent studies have provided new insights into the complexity of the endocytic pathways originating at the plasma membrane of mammalian cells. Many of the molecules involved in clathrin coated pit internalization are now well understood but other pathways are less well defined. Caveolae appear to represent a low capacity but highly regulated pathway in a restricted set of tissues in vivo. A third pathway, which is both clathrin- and caveolae-independent, may constitute a specialized high capacity endocytic pathway for lipids and fluid. The relationship of this pathway, if any, to macropinocytosis or to the endocytic pathways of lower eukaryotes remains an interesting open question. Our understanding of the regulatory mechanisms and molecular components involved in this pathway are at a relatively primitive stage. In this review, we will consider some of the characteristics of different endocytic pathways in high and lower eukaryotes and consider some of the common themes in endocytosis. One theme which becomes apparent from comparison of these pathways is that apparently different pathways can share common molecular machinery and that pathways considered to be distinct actually represent similar basic pathways to which additional levels of regulatory complexity have been added.
最近的一些研究为源自哺乳动物细胞质膜的内吞途径的复杂性提供了新的见解。目前，许多参与网格蛋白包被小窝内化的分子已被深入了解，但其他途径的定义尚不明确。在体内特定的一组组织中，小窝似乎代表了一种低容量但高度受调控的途径。第三条途径既不依赖网格蛋白也不依赖小窝，可能构成一种专门用于脂质和液体的高容量内吞途径。这条途径（如果有的话）与巨吞饮作用或低等真核生物的内吞途径之间的关系仍然是一个有趣的悬而未决的问题。我们对这条途径中涉及的调控机制和分子成分的理解仍处于相对初级的阶段。在这篇综述中，我们将考虑高等和低等真核生物中不同内吞途径的一些特征，并探讨内吞作用中的一些共同主题。通过比较这些途径可以明显看出一个主题，即看似不同的途径可以共享共同的分子机制，那些被认为不同的途径实际上代表了相似的基本途径，只不过增加了额外层次的调控复杂性。
