Mandl József, Bánhegyi Gábor
Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary.
Pathol Oncol Res. 2018 Oct;24(4):821-826. doi: 10.1007/s12253-018-0446-0. Epub 2018 Jul 7.
Glycogen particle is an intracellular organelle, which serves as a carbohydrate reserve in various cells. The function of glycogen is not entirely known in several cell types. Glycogen can be mobilized for different purposes, which can be related to cellular metabolic needs, intracellular redox state, metabolic state of the whole organism depending on regulatory aspects and also on cell functions. Essentially there are two different ways of glycogen degradation localized in different cellular organelles: glycogenolysis or lysosomal breakdown by acid alpha-glucosidase. While glycogenolysis occurs in glycogen particles connected to endoplasmic reticulum membrane, glycogen particles can be also combined with phagophores forming autophagosomes. A subdomain of the endoplasmic reticulum membrane - omegasomes - are the sites for phagophore formation. Thus, three organelles, the endoplasmic reticulum, the phagophore and the glycogen particle forms a triangle in which glycogen degradation occurs. The physiological significance, molecular logic and regulation of the two different catabolic paths are summarized and discussed with special aspect on the role of glycogen particles in intracellular organelle homeostasis and on molecular pathology of the cell. Pathological aspects and some diseases connected to the two different degradation pathways of glycogen particles are also detailed.
糖原颗粒是一种细胞内细胞器，在各种细胞中作为碳水化合物储备。在几种细胞类型中，糖原的功能尚不完全清楚。糖原可因不同目的而被动员，这可能与细胞代谢需求、细胞内氧化还原状态、取决于调节因素的整个生物体的代谢状态以及细胞功能有关。本质上，糖原降解存在两种不同方式，分别定位于不同的细胞器：糖原分解或由酸性α-葡萄糖苷酶进行的溶酶体分解。糖原分解发生在与内质网膜相连的糖原颗粒中，糖原颗粒也可与吞噬泡结合形成自噬体。内质网膜的一个亚结构域——ω-小体——是吞噬泡形成的部位。因此，内质网、吞噬泡和糖原颗粒这三种细胞器形成一个三角形，糖原降解在此发生。本文总结并讨论了这两种不同分解途径的生理意义、分子逻辑和调节，特别关注糖原颗粒在细胞内细胞器稳态中的作用以及细胞的分子病理学。还详细阐述了与糖原颗粒两种不同降解途径相关的病理方面和一些疾病。
