Rab35, a member of the Rab GTPase family, has been implicated in various cellular processes including cell motility and membrane trafficking. Although Rab35 is localized to the plasma membrane, Rab proteins that are identified to have high sequence homology with Rab35 exhibit distinct subcellular localization patterns. Comparing the amino acid sequences between Rab35 and its family members revealed a significant variation in an approximate 30-amino acid region of the C-terminus. This suggests that this region determines the subcellular localization of individual Rab proteins. To confirm this hypothesis, we constructed Rab35–Rab10 chimera proteins by exchanging their C-terminal domains with one another. Confocal microscopy of RAW264 cells expressing EGFP-fused Rab35–Rab10 chimeras has indicated that the C-terminal region of Rab35 is critical for its plasma membrane localization. Furthermore, we were able to determine that a basic amino acid cluster exists in the C-terminal region of Rab35 and that Rab35 localization shifts to the Golgi membrane when the number of basic amino acids in this region is reduced. Thus, it is likely that the approximate 30-amino acid C-terminal region containing basic clusters is responsible for Rab35 plasma membrane localization and that its preferential localization depends on the number of basic amino acids.

Rab35是Rab GTPase家族的成员，已参与各种细胞过程，包括细胞运动性和膜运输。尽管Rab35定位于质膜，但与Rab35具有高度序列同源性的Rab蛋白表现出不同的亚细胞定位模式。比较Rab35及其家族成员之间的氨基酸序列，发现C端大约30个氨基酸区域有显着变化。这表明该区域决定了单个Rab蛋白的亚细胞定位。为了证实这一假设，我们通过相互交换Rab35–Rab10嵌合蛋白构建了它们的C端结构域。表达EGFP融合的Rab35–Rab10嵌合体的RAW264细胞的共聚焦显微镜观察表明，Rab35的C端区域对于其质膜定位至关重要。此外，我们能够确定在Rab35的C端区域中存在一个碱性氨基酸簇，并且当该区域中的碱性氨基酸数量减少时，Rab35的定位会转移到高尔基膜上。因此，可能含有大约30个氨基酸的C端碱性碱基簇负责Rab35质膜的定位，其优先定位取决于碱性氨基酸的数量。我们能够确定在Rab35的C端区域中存在一个碱性氨基酸簇，并且当该区域中的碱性氨基酸数量减少时，Rab35的定位会转移到高尔基膜上。因此，可能含有大约30个氨基酸的C端碱性碱基簇负责Rab35质膜的定位，并且其优先定位取决于碱性氨基酸的数目。我们能够确定在Rab35的C端区域中存在一个碱性氨基酸簇，并且当该区域中的碱性氨基酸数量减少时，Rab35的定位会转移到高尔基膜上。因此，可能含有大约30个氨基酸的C端碱性碱基簇负责Rab35质膜的定位，并且其优先定位取决于碱性氨基酸的数目。