Division of Molecular and Life Sciences and Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea.
Traffic. 2011 Feb;12(2):185-200. doi: 10.1111/j.1600-0854.2010.01140.x. Epub 2010 Dec 1.
Prenylated Rab acceptors (PRAs) bind to prenylated Rab proteins and possibly aid in targeting Rabs to their respective compartments. In Arabidopsis, 19 isoforms of PRA1 have been identified and, depending upon the isoforms, they localize to the endoplasmic reticulum (ER), Golgi apparatus and endosomes. Here, we investigated the localization and trafficking of AtPRA1.B6, an isoform of the Arabidopsis PRA1 family. In colocalization experiments with various organellar markers, AtPRA1.B6 tagged with hemagglutinin (HA) at the N-terminus localized to the Golgi apparatus in protoplasts and transgenic plants. The valine residue at the C-terminal end and an EEE motif in the C-terminal cytoplasmic domain were critical for anterograde trafficking from the ER to the Golgi apparatus. The N-terminal region contained a sequence motif for retention of AtPRA1.B6 at the Golgi apparatus. In addition, anterograde trafficking of AtPRA1.B6 from the ER to the Golgi apparatus was highly sensitive to the HA:AtPRA1.B6 level. The region that contains the sequence motif for Golgi retention also conferred the abundance-dependent trafficking inhibition. On the basis of these results, we propose that AtPRA1.B6 localizes to the Golgi apparatus and its ER-to-Golgi trafficking and localization to the Golgi apparatus are regulated by multiple sequence motifs in both the C- and N-terminal cytoplasmic domains.
prenylated Rab 受体（PRAs）与 prenylated Rab 蛋白结合，并可能有助于将 Rab 蛋白靶向其各自的隔室。在拟南芥中，已经鉴定出 19 种 PRA1 同工型，根据同工型的不同，它们定位于内质网（ER）、高尔基体和内体。在这里，我们研究了拟南芥 PRA1 家族的同工型 AtPRA1.B6 的定位和运输。在用各种细胞器标记物进行共定位实验中，AtPRA1.B6 在 N 端带有血凝素（HA）标签，在原生质体和转基因植物中定位于高尔基体。C 末端的缬氨酸残基和 C 末端细胞质结构域中的 EEE 基序对于从 ER 到高尔基体的正向运输是至关重要的。N 端区域包含一个使 AtPRA1.B6 在高尔基体中保留的序列基序。此外，AtPRA1.B6 从 ER 到高尔基体的正向运输对 HA:AtPRA1.B6 水平非常敏感。包含高尔基体保留序列基序的区域还赋予了丰度依赖性的运输抑制。基于这些结果，我们提出 AtPRA1.B6 定位于高尔基体，其 ER 到高尔基体的运输和定位到高尔基体受到 C 端和 N 端细胞质结构域中多个序列基序的调节。
