Brown adipose tissue (BAT), present in many placental mammals, provides adaptive nonshivering thermogenesis (NST) for body temperature regulation and has facilitated survival in diverse thermal niches on our planet. Intriguingly, several key details on the molecular mechanisms of NST and their potential ecophysiological adaptations are still unknown. Comparative studies at the whole animal level are unpragmatic, due to the diversity and complexity of thermoregulation among different species. We propose that the molecular evolution of mitochondrial uncoupling protein 1 (UCP1), a central component for BAT thermogenesis, represents a powerful opportunity to unravel key questions of mammalian thermoregulation. Comparative analysis of UCP1 may elucidate how its thermogenic function arose, how environmental selection has shaped protein function to support ecophysiological requirements, and how the enigmatic molecular mechanism of proton leak is governed. Several approaches for the assessment of UCP1 function in vitro have been introduced over the years. For comparative characterization of UCP1, we put forward the overexpression of UCP1 orthologues and mutated variants in a mammalian cell system as a primary strategy and discuss advantageous aspects in contrast to other experimental systems. In turn, we suggest how remaining experimental caveats can be solved by complimentary test systems before physiological consolidation in the animal model. Furthermore, we highlight the appropriate bioenergetic techniques to perform the functional analyses on UCP1. The comparative characterizations of diverse UCP1 variants may enable key insights into open questions surrounding the molecular basis of NST.

棕色脂肪组织 (BAT) 存在于许多胎盘哺乳动物中，为体温调节提供适应性非颤抖产热 (NST)，并促进了我们星球上不同热环境中的生存。有趣的是，关于 NST 分子机制及其潜在生态生理适应的几个关键细节仍然未知。由于不同物种之间体温调节的多样性和复杂性，在整个动物水平上进行比较研究是不切实际的。我们提出，线粒体解偶联蛋白 1 (UCP1) 是 BAT 产热的核心成分，其分子进化代表了解开哺乳动物体温调节关键问题的强大机会。UCP1 的比较分析可能阐明其产热功能是如何产生的，环境选择如何塑造蛋白质功能以支持生态生理需求，以及如何控制质子泄漏的神秘分子机制。多年来，已经引入了几种体外评估 UCP1 功能的方法。对于 UCP1 的比较表征，我们提出在哺乳动物细胞系统中过表达 UCP1 直向同源物和突变变体作为主要策略，并讨论与其他实验系统相比的优势方面。反过来，我们建议如何在动物模型的生理巩固之前通过补充测试系统解决剩余的实验警告。此外，我们强调了适当的生物能技术来对 UCP1 进行功能分析。