Abdollahi Sisi Nayyer, Růžička Kamil
Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague, Czech Republic.
Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czech Republic.
Plants (Basel). 2020 Nov 10;9(11):1527. doi: 10.3390/plants9111527.
The proper distribution of the hormone auxin is essential for plant development. It is channeled by auxin efflux carriers of the PIN family, typically asymmetrically located on the plasma membrane (PM). Several studies demonstrated that some PIN transporters are also located at the endoplasmic reticulum (ER). From the PM-PINs, they differ in a shorter internal hydrophilic loop, which carries the most important structural features required for their subcellular localization, but their biological role is otherwise relatively poorly known. We discuss how ER-PINs take part in maintaining intracellular auxin homeostasis, possibly by modulating the internal levels of IAA; it seems that the exact identity of the metabolites downstream of ER-PINs is not entirely clear as well. We further review the current knowledge about their predicted structure, evolution and localization. Finally, we also summarize their role in plant development.
激素生长素的正确分布对植物发育至关重要。它通过PIN家族的生长素外流载体进行运输，这些载体通常不对称地位于质膜（PM）上。多项研究表明，一些PIN转运蛋白也位于内质网（ER）。与质膜PIN蛋白相比，它们的内部亲水环较短，该亲水环具有亚细胞定位所需的最重要结构特征，但其生物学作用相对鲜为人知。我们讨论了内质网PIN蛋白如何参与维持细胞内生长素稳态，可能是通过调节IAA的内部水平；内质网PIN蛋白下游代谢物的确切身份似乎也不完全清楚。我们还进一步综述了关于它们预测结构、进化和定位的现有知识。最后，我们总结了它们在植物发育中的作用。
