Lmna yields two major protein products in somatic cells, lamin C and prelamin A. Mature lamin A is produced from prelamin A by four posttranslational processing steps-farnesylation of a carboxyl-terminal cysteine, release of the last three amino acids of the protein, methylation of the farnesylcysteine, and the endoproteolytic release of the carboxyl-terminal 15 amino acids of the protein (including the farnesylcysteine methyl ester). Although the posttranslational processing of prelamin A has been conserved in vertebrate evolution, its physiologic significance remains unclear. Here we review recent studies in which we investigated prelamin A processing with Lmna knock-in mice that produce exclusively prelamin A (Lmna(PLAO)), mature lamin A (Lmna(LAO)) or nonfarnesylated prelamin A (Lmna(nPLAO)). We found that the synthesis of lamin C is dispensable in laboratory mice, that the direct production of mature lamin A (completely bypassing all prelamin A processing) causes no discernable pathology in mice, and that exclusive production of nonfarnesylated prelamin A leads to cardiomyopathy.

中文翻译：

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调查prelamin A处理的目的

Lmna 在体细胞中产生两种主要的蛋白质产物，核纤层蛋白 C 和 prelamin A。成熟的核纤层蛋白 A 由 prelamin A 通过四个翻译后加工步骤产生——羧基末端半胱氨酸的法尼基化、蛋白质最后三个氨基酸的释放、甲基化法呢基半胱氨酸的释放，以及蛋白质羧基末端 15 个氨基酸（包括法呢基半胱氨酸甲酯）的内蛋白酶解释放。虽然 prelamin A 的翻译后加工在脊椎动物进化中是保守的，但其生理意义仍不清楚。在这里，我们回顾了最近的研究，其中我们研究了用 Lmna 敲入小鼠进行的 prelamin A 加工，这些小鼠仅产生 prelamin A (Lmna(PLAO))、成熟的 lamin A (Lmna(LAO)) 或 nonfarnesylated prelamin A (Lmna(nPLAO))。