Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, São Paulo, Brazil.
Arch Dermatol Res. 2013 Dec;305(10):857-66. doi: 10.1007/s00403-013-1415-9. Epub 2013 Oct 2.
Epithelial tissues are specialized to protect underlying tissues from environmental influences such as physical and chemical agents, infection by invasive microorganisms as well as water and heat loss. They are grouped into simple, transitional and stratified epithelia, which line the cavities and surfaces of structures throughout the body, and also form glands, separate compartments, regulate the exchange of molecules and act as sensory organs. Stratified epithelia such as the epidermis and the gingival and hard palate mucosa are in constant renewal, with cells proliferating in the lower layers, while the intermediate stratum and outermost layers undergo a tissue-specific process of differentiation to form a protective cornified barrier. This review focuses on a subclass of structural proteins, the small proline-rich proteins (SPRRs), which constitute cornified cell envelope precursors. Several studies have suggested that the SPRRs are related to increased epithelial proliferation and to malignant processes. Hence, we also review the literature for more extensive and in-depth profile of these proteins in cancer and other diseases. The understanding of SPRR functions has advanced in recent years, but many important questions about their role in pathophysiological processes remain unanswered, which stimulate new studies and approaches.
上皮组织专门用于保护下层组织免受环境影响，如物理和化学制剂、入侵微生物的感染以及水和热量的流失。它们分为简单、过渡和复层上皮，这些上皮组织覆盖着全身结构的腔和表面，也形成腺体、分隔腔室、调节分子交换并作为感觉器官。复层上皮，如表皮和牙龈及硬腭黏膜，处于持续更新状态，下层细胞增殖，而中间层和最外层则经历组织特异性的分化过程，形成保护性角化屏障。本文重点介绍了一小类结构蛋白，即富含脯氨酸的小蛋白（SPRRs），它们是角化细胞包膜的前体。多项研究表明，SPRRs 与上皮细胞增殖增加和恶性过程有关。因此，我们还回顾了这些蛋白质在癌症和其他疾病中的更广泛和深入的文献。近年来，对 SPRR 功能的理解有所进展，但关于它们在生理病理过程中的作用仍有许多重要问题尚未得到解答，这激发了新的研究和方法。
