Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
PLoS One. 2018 Nov 7;13(11):e0206944. doi: 10.1371/journal.pone.0206944. eCollection 2018.
The arrestin-related family of proteins (ARTs) are potent regulators of membrane traffic at multiple cellular locations in the yeast Saccharomyces cerevisiae. Several ARTs act at multiple locations, suggesting that ARTs with well-established functions at one location may have additional, as of yet, uncharacterized roles at other locations in the cell. To more fully understand the spectrum of cellular functions regulated by ART proteins, we explored the localization and function of Ldb19/Art1, which has previously been shown to function at the plasma membrane, yet is reported to localize to the trans-Golgi network (TGN). We report that the C-terminal fusion of Ldb19 with GFP is functional and, as previously reported, localizes to the TGN. We further establish that Ldb19 associates with late stages of TGN maturation that are enriched in the clathrin adaptor protein complex-1 (AP-1). Additionally, we present genetic interaction assays that suggest Ldb19 acts at the late TGN in a mechanism related to that of AP-1. However, Ldb19 and AP-1 have dissimilar phenotypes in a subset of assays of membrane traffic, suggesting Ldb19 functions at the TGN are distinct from those of AP-1. Together these results indicate Ldb19 functions at the TGN, in addition to its well-established role in endocytosis.
arrestin 相关蛋白家族 (ARTs) 是酵母酿酒酵母中多个细胞位置膜运输的有效调节剂。几种 ARTs 在多个位置起作用，这表明在一个位置具有既定功能的 ARTs 可能在细胞的其他位置具有额外的、尚未被描述的作用。为了更全面地了解 ART 蛋白调节的细胞功能谱，我们研究了 Ldb19/Art1 的定位和功能，此前已证明它在质膜上发挥作用，但据报道其定位在高尔基网络 (TGN)。我们报告说，Ldb19 与 GFP 的 C 端融合是有功能的，并且如前所述，定位在 TGN。我们进一步确定 Ldb19 与富含网格蛋白衔接蛋白复合物-1 (AP-1) 的 TGN 晚期成熟阶段相关联。此外，我们提出了遗传相互作用测定，表明 Ldb19 在与 AP-1 相关的机制中在晚期 TGN 中起作用。然而，在膜运输的某些测定中，Ldb19 和 AP-1 具有不同的表型，这表明 Ldb19 在 TGN 中的功能与 AP-1 不同。这些结果表明 Ldb19 在 TGN 中发挥作用，除了其在胞吞作用中的既定作用。
