The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors, particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues, by involving not only different ligand binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Noteworthy, dysregulation of the IR-A:IR-B ratio is associated with insulin resistance, aging and increased proliferative activity of normal and neoplastic tissues, and appears to sustain detrimental effects.

中文翻译：

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生理学和疾病中的胰岛素受体亚型：最新观点

胰岛素受体 (IR) 基因经历差异剪接，产生两种 IR 亚型：IR-A 和 IR-B。IR 同工型的生理作用尚不完全清楚，似乎是由它们对胰岛素样生长因子（尤其是 IGF-2）的不同结合亲和力决定的。IR-A 在产前生长和发育中的主要作用以及 IR-B 在代谢调节中的主要作用已得到充分证实。然而，新出现的证据表明，IR亚型的差异表达也可能有助于解释不同器官和组织中胰岛素和IGF信号传导和作用的多样化，不仅涉及不同的配体结合亲和力，还涉及不同的膜分区和运输以及可能不同的能力与各种分子伙伴相互作用。值得注意的是，IR-A:IR-B 比例失调与胰岛素抵抗、衰老以及正常组织和肿瘤组织增殖活性增加有关，并且似乎会产生有害影响。