IFM, Linköping University, 581 83 Linköping, Sweden
IFM, Linköping University, 581 83 Linköping, Sweden.
J Lipid Res. 2018 Aug;59(8):1374-1382. doi: 10.1194/jlr.R083139. Epub 2018 Mar 19.
The nonspecific lipid transfer proteins (LTPs) are small compact proteins folded around a tunnel-like hydrophobic cavity, making them suitable for lipid binding and transport. LTPs are encoded by large gene families in all land plants, but they have not been identified in algae or any other organisms. Thus, LTPs are considered key proteins for plant survival on and colonization of land. LTPs are abundantly expressed in most plant tissues, both above and below ground. They are usually localized to extracellular spaces outside the plasma membrane. Although the in vivo functions of LTPs remain unclear, accumulating evidence suggests a role for LTPs in the transfer and deposition of monomers required for assembly of the waterproof lipid barriers, such as cutin and cuticular wax, suberin, and sporopollenin, formed on many plant surfaces. Some LTPs may be involved in other processes, such as signaling during pathogen attacks. Here, we present the current status of LTP research with a focus on the role of these proteins in lipid barrier deposition and cell expansion. We suggest that LTPs facilitate extracellular transfer of barrier materials and adhesion between barriers and extracellular materials. A growing body of research may uncover the true role of LTPs in plants.
非特异性脂质转移蛋白（LTPs）是一种小型紧凑的蛋白质，折叠在一个类似隧道的疏水性腔周围，使其适合于脂质结合和运输。LTPs 存在于所有陆地植物的大型基因家族中，但在藻类或任何其他生物中都没有发现。因此，LTPs 被认为是植物在陆地上生存和定殖的关键蛋白。LTPs 在大多数植物组织中大量表达，包括地上和地下组织。它们通常定位于质膜外的细胞外空间。虽然 LTPs 的体内功能尚不清楚，但越来越多的证据表明，LTPs 在转移和沉积组装防水脂质屏障所需的单体中发挥作用，如在许多植物表面形成的角质、角质蜡、栓质和花粉外壁。一些 LTPs 可能参与其他过程，如病原体攻击期间的信号转导。本文重点介绍了这些蛋白质在脂质屏障沉积和细胞扩展中的作用，介绍了 LTP 研究的现状。我们提出 LTPs 促进了屏障材料的细胞外转移以及屏障和细胞外材料之间的黏附。越来越多的研究可能揭示 LTPs 在植物中的真正作用。
