Human skeletal muscle is a heterogeneous tissue composed of multiple fiber types that express unique contractile and metabolic properties. While analysis of mixed fiber samples predominates and holds value, increasing attention has been directed towards studying proteins segregated by fiber type, a methodological distinction termed "fiber type-specific." Fiber type-specific protein studies have the advantage of uncovering key molecular effects that are often missed in mixed fiber homogenate studies but also require greater time and resource-intensive methods, particularly when applied to human muscle. This review summarizes and compares current methods used for fiber type-specific protein analysis, highlighting their advantages and disadvantages for human muscle studies, in addition to recent advances in these techniques. These methods can be grouped into 3 categories based on the initial processing of the tissue: 1) muscle-specific fiber homogenates, 2) cross-sections of fiber bundles, and 3) isolated single fibers, with various sub-techniques for performing fiber type identification and protein quantification. The relative implementation for each unique methodological approach is analyzed from 83 fiber type-specific studies of proteins in live human muscle found in the literature to-date. These studies have investigated several proteins involved in a wide range of cellular functions that are important to muscle tissue. The second half of this review summarizes key findings from this ensemble of fiber type-specific human protein studies. We highlight examples of where this analytical approach has helped to improve understanding of important physiological topics such as insulin sensitivity, muscle hypertrophy, muscle fatigue, and adaptation to different exercise programs.

中文翻译：

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推动人类肌肉生理学研究的发展：对特定于纤维类型的蛋白质研究方法的评估。

人的骨骼肌是由多种纤维组成的异质组织，它们表达独特的收缩和代谢特性。尽管混合纤维样品的分析占主导地位并具有价值，但越来越多的注意力转向研究按纤维类型分离的蛋白质，这种方法学上的区别称为“特定于纤维类型”。特定于纤维类型的蛋白质研究的优势在于发现了关键分子效应，而混合纤维匀浆研究常常忽略了这些分子效应，但是还需要更多的时间和资源密集型方法，尤其是应用于人体肌肉时。这篇综述总结并比较了目前用于纤维类型特异性蛋白质分析的方法，并重点介绍了这些方法在人类肌肉研究中的利弊，以及这些技术的最新进展。根据组织的初始处理，这些方法可以分为3类：1）肌肉特异性纤维匀浆，2）纤维束的横截面和3）分离的单纤维，以及用于执行纤维类型的各种子技术鉴定和蛋白质定量。迄今为止，已有83篇关于人类活肌中蛋白质的纤维类型特异性研究对每种独特方法论方法的相对实施方法进行了分析。这些研究已经研究了多种蛋白质，这些蛋白质对肌肉组织很重要，涉及广泛的细胞功能。这篇综述的后半部分总结了这一由纤维类型特异性人类蛋白质研究组成的集合的主要发现。