FNDC5 corresponds to an irisin precursor that increases with exercise. Studies suggest that irisin mediates beneficial effects in adipose tissues, skeletal muscle, bone, and brain. However, the cleavage and maturation processes of FNDC5 have not been clearly identified. This study aimed to show that the signal peptide and transmembrane domain of FNDC5 were associated with the secretion of its ectodomain. Localization studies identified the signal peptide that was responsible for endoplasmic reticulum targeting activity of nascent FNDC5 and showed that the FNDC5 ectodomain corresponding to irisin could be transported across the membrane by a transmembrane domain. Analysis of cleavage constructs revealed that the ectodomain of FNDC5 could be cleaved from its signal peptide and transmembrane attachment. Genetic ablation of the signal peptide cleavage site blocked N-glycosylation of FNDC5. Identification of the FNDC5 maturation process should facilitate our understanding of irisin secretion.

中文翻译：

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FNDC5的切割及其成熟过程的见解。

FNDC5对应于随运动增加的虹膜素前体。研究表明，鸢尾素在脂肪组织，骨骼肌，骨骼和大脑中介导有益作用。但是，FNDC5的分裂和成熟过程尚未明确。这项研究旨在表明FNDC5的信号肽和跨膜结构域与其胞外结构域的分泌有关。定位研究确定了负责新生FNDC5内质网靶向活性的信号肽，并表明与虹膜素相对应的FNDC5胞外域可以通过跨膜结构域跨膜转运。切割构建体的分析表明，FNDC5的胞外域可以从其信号肽和跨膜附着中被切割。信号肽切割位点的遗传消融阻止了FNDC5的N-糖基化。FNDC5成熟过程的鉴定应有助于我们了解虹膜素的分泌。