Lysosomal integral membrane protein-2 (LIMP-2) is a type III transmembrane protein that is highly glycosylated and mainly localized to the lysosomal membrane. The diverse functions of LIMP-2 are currently being uncovered; however, its participation in macroautophagy, usually described as autophagy, has not yet been well-investigated. To determine the possible involvement of LIMP-2 in autophagic activity, we examined the intracellular amount of microtubule-associated protein 1 light chain 3 (LC3)-II, which is well-correlated with autophagosome levels, in exogenous rat LIMP-2-expressing COS7 and HEK293 cells. Transient or stable expression of LIMP-2-myc significantly increased the levels of LC3-II. Conversely, knockdown of LIMP-2 decreased the LC3-II levels in NIH3T3 cells. Furthermore, approaches using lysosomal protease inhibitors and mCherry-GFP-LC3 fluorescence suggested that exogenous expression of LIMP-2 increased the biogenesis of autophagosomes rather than decreased the lysosomal turnover of LC3-II. Considering the results of the biochemical assay and the quantitative fluorescence assay together, it is suggested that LIMP-2 has a possible involvement in autophagic activity, especially autophagosome biogenesis.

溶酶体整合膜蛋白2（LIMP-2）是III型跨膜蛋白，高度糖基化，主要定位在溶酶体膜上。LIMP-2的各种功能目前正在被发现。然而，其参与宏观自噬（通常称为自噬）的研究尚未得到充分研究。为了确定LIMP-2可能参与自噬活动，我们检查了外源大鼠LIMP-2表达中微管相关蛋白1轻链3（LC3）-II的细胞内数量，该蛋白与自噬体水平高度相关。 COS7和HEK293细胞。LIMP-2-myc的瞬时或稳定表达显着提高了LC3-II的水平。相反，敲低LIMP-2可降低NIH3T3细胞中的LC3-II水平。此外，使用溶酶体蛋白酶抑制剂和mCherry-GFP-LC3荧光的方法表明，LIMP-2的外源表达增加了自噬体的生物发生，而不是降低了LC3-II的溶酶体更新。综合考虑生化测定和定量荧光测定的结果，提示LIMP-2可能参与自噬活性，尤其是自噬体的生物发生。