Institut für Biochemie, Universität Stuttgart, Stuttgart, Germany.
FEBS Lett. 2011 Dec 15;585(24):3856-61. doi: 10.1016/j.febslet.2011.10.038. Epub 2011 Oct 29.
The two major antagonistic pathways of carbon metabolism in cells, glycolysis and gluconeogenesis, are tightly regulated. In the eukaryotic model organism Saccharomyces cerevisiae the switch from gluconeogenesis to glycolysis is brought about by proteasomal degradation of the gluconeogenic enzyme fructose-1,6-bisphosphatase. The ubiquitin ligase responsible for polyubiquitylation of fructose-1,6-bisphosphatase is the Gid complex. This complex consists of seven subunits of which subunit Gid2/Rmd5 contains a RING finger domain providing E3 ligase activity. Here we identify an additional subunit containing a degenerated RING finger, Gid9/Fyv10. This subunit binds to Gid2/Rmd5. A mutation in the degenerated RING finger of Gid9/Fyv10 abolishes polyubiquitylation and degradation of three enzymes specific for gluconeogenesis.
细胞中碳代谢的两条主要拮抗途径，糖酵解和糖异生，受到严格调控。在真核模式生物酿酒酵母中，从糖异生到糖酵解的转变是通过蛋白酶体降解糖异生酶果糖-1,6-二磷酸酶实现的。负责果糖-1,6-二磷酸酶多泛素化的泛素连接酶是 Gid 复合物。该复合物由七个亚基组成，其中亚基 Gid2/Rmd5 含有一个 RING 指结构域，提供 E3 连接酶活性。在这里，我们鉴定出一个含有退化 RING 指的额外亚基 Gid9/Fyv10。该亚基与 Gid2/Rmd5 结合。Gid9/Fyv10 中退化 RING 指的突变会破坏三种专门参与糖异生的酶的多泛素化和降解。
