Title : Biosynthesis and post-translational processing of the
precursor to
brain-derived neurotrophic factor
Abstract :
- We examined the biosynthesis and post-translational processing of the brain-derived neurotrophic factor precursor ( pro- BDNF ) in cells infected with a pro- BDNF-encoding vaccinia virus
- Metabolic labeling, immunoprecipitation, and SDS-polyacrylamide gel electrophoresis reveal that pro- BDNF is generated as a 32-kDa precursor that is N-glycosylated and glycosulfated on a site , within the pro-domain
- Some pro- BDNF is released extracellularly and is biologically active as demonstrated by its ability to mediate TrkB phosphorylation
- The precursor undergoes N-terminal cleavage within the trans-Golgi network and/or immature secretory vesicles to generate mature BDNF (14 kDa)
- Small amounts of a 28-kDa protein that is immunoprecipitated with BDNF antibodies is also evident
- This protein is generated in the endoplasmic reticulum through N-terminal cleavage of pro- BDNF at the Arg-Gly-Leu-Thr(57)- downward arrow-Ser-Leu site
- Cleavage is abolished when Arg(54) is changed to Ala (R54A) by in vitro mutagenesis
- Blocking generation of 28-kDa BDNF has no effect on the level of mature BDNF and blocking generation of mature BDNF with alpha(1)-PDX, an inhibitor of furin-like enzymes , does not lead to accumulation of the 28-kDa form
- These data suggest that 28-kDa pro- BDNF is not an obligatory intermediate in the formation of the 14-kDa form in the constitutive secretory pathway