MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
FEBS Lett. 2019 Sep;593(17):2452-2465. doi: 10.1002/1873-3468.13553. Epub 2019 Aug 8.
The Golgi apparatus is an important site for the modification of most secreted and membrane proteins. Glycan processing is the major class of modification and is mediated by a large number of Golgi-resident glycosyltransferases and glycosidases. These Golgi enzymes are largely type II transmembrane domain (TMD) proteins consisting of a short N-terminal cytosolic tail, a relatively short TMD and a lumenal 'stem/stalk' region which acts as a spacer between the catalytic domain and the lipid bilayer. The cytosolic tail, TMD, and stem together make what is termed the CTS domain which is responsible for the specific localisation of these enzymes within sub-Golgi compartments via multiple mechanisms. In addition, the catalytic domains of some Golgi enzymes are secreted as a consequence of proteolytic cleavage within their TMDs or stem regions. Finally, there is evidence to suggest that when the retention of Golgi enzymes is perturbed they are targeted for lysosomal degradation.
高尔基体是大多数分泌蛋白和膜蛋白修饰的重要场所。糖基化加工是主要的修饰类型，由大量驻留在高尔基体中的糖基转移酶和糖苷酶介导。这些高尔基体酶主要是 II 型跨膜结构域（TMD）蛋白，由短的 N 端胞质尾、相对较短的 TMD 和腔侧“茎/干”区组成，后者作为催化结构域和脂质双层之间的间隔物。胞质尾、TMD 和茎一起构成所谓的 CTS 结构域，通过多种机制负责这些酶在亚高尔基体隔室中的特异性定位。此外，一些高尔基体酶的催化结构域通过其 TMD 或茎区的蛋白水解切割而被分泌。最后，有证据表明，当高尔基体酶的保留受到干扰时，它们被靶向溶酶体降解。
