Teng Linhong, Sun Yuhuan, Chen Jiayi, Wang Chenghui, Urbach Jonathan M, Kobe Bostjan, Ye Naihao, Zeng Qiangcheng
College of Life Sciences, Dezhou University, Dezhou, China.
Ragon Institute of Mass General Brigham, MIT, and Harvard, Cambridge, MA, United States.
Front Plant Sci. 2024 Aug 23;15:1445022. doi: 10.3389/fpls.2024.1445022. eCollection 2024.
The ROCO family is a family of GTPases characterized by a central ROC-COR tandem domain. Interest in the structure and function of ROCO proteins has increased with the identification of their important roles in human disease. Nevertheless, the functions of most ROCO proteins are still unknown. In the present study, we characterized the structure, evolution, and expression of ROCOs in four species of brown algae. Brown algae have a larger number of ROCO proteins than other organisms reported to date. Phylogenetic analyses showed that ROCOs have an ancient origin, likely originated in prokaryotes. ROCOs in brown algae clustered into four groups and showed no strong relationship with red algae or green algae. Brown algal ROCOs retain the ancestral LRR-ROC-COR domain arrangement, which is found in prokaryotes, plants and some basal metazoans. Remarkably, individual LRR motifs in ROCO genes are each encoded by separate exons and exhibit intense exon shuffling and diversifying selection. Furthermore, the tandem LRR exons exhibit alternative splicing to generate multiple transcripts. Both exon shuffling and alternative splicing of LRR repeats may be important mechanisms for generating diverse ligand-binding specificities as immune receptors. Besides their potential immune role, expression analysis shows that many ROCO genes are responsive to other stress conditions, suggesting they could participate in multiple signal pathways, not limited to the immune response. Our results substantially enhance our understanding of the structure and function of this mysterious gene family.
ROCO家族是一类GTP酶家族，其特征在于具有一个中央ROC - COR串联结构域。随着ROCO蛋白在人类疾病中的重要作用被发现，人们对其结构和功能的兴趣与日俱增。然而，大多数ROCO蛋白的功能仍然未知。在本研究中，我们对四种褐藻中ROCO蛋白的结构、进化和表达进行了表征。褐藻中的ROCO蛋白数量比迄今为止报道的其他生物更多。系统发育分析表明，ROCO蛋白起源古老，可能起源于原核生物。褐藻中的ROCO蛋白聚为四类，与红藻或绿藻没有密切关系。褐藻ROCO蛋白保留了原核生物、植物和一些基础后生动物中发现的祖先LRR - ROC - COR结构域排列。值得注意的是，ROCO基因中的单个LRR基序各自由单独的外显子编码，并表现出强烈的外显子重排和多样化选择。此外，串联LRR外显子表现出可变剪接以产生多种转录本。LRR重复序列的外显子重排和可变剪接都可能是作为免疫受体产生多样配体结合特异性的重要机制。除了其潜在的免疫作用外，表达分析表明许多ROCO基因对其他应激条件有反应，这表明它们可能参与多种信号通路，不限于免疫反应。我们的结果极大地增进了我们对这个神秘基因家族结构和功能的理解。
