PMID- 9654087
OWN - NLM
STAT- MEDLINE
DCOM- 19980717
LR  - 20191210
IS  - 0014-2956 (Print)
IS  - 0014-2956 (Linking)
VI  - 253
IP  - 2
DP  - 1998 Apr 15
TI  - Tyrosine phosphorylation of the muscle-specific kinase is exclusively induced by 
      acetylcholine receptor-aggregating agrin fragments.
PG  - 382-9
AB  - During formation of the neuromuscular junction, the basal membrane protein agrin 
      initiates the aggregation of acetylcholine receptors (AChR) on the surface of 
      myotubes. A muscle-specific kinase (MuSK) becomes phosphorylated upon incubation 
      with agrin, although it does not bind to agrin on its own. Utilizing 
      MuSK-specific antibodies, we demonstrate that the ability of different splicing 
      variants and truncation fragments of agrin to trigger MuSK phosphorylation and 
      AChR aggregation are correlated. Only agrin forms which are potent inducers of 
      AChR-clustering are able to trigger the phosphorylation of MuSK. Picomolar 
      concentrations of agrin are already sufficient to induce MuSK phosphorylation. 
      Similar amounts are necessary for the aggregation of AChRs as well as their 
      phosphorylation on a tyrosine residue. The complete overlap of specificities for 
      MuSK phosphorylation and AChR aggregation suggests that only binding of agrin to 
      a MuSK-containing receptor complex is responsible for the initiation of AChR 
      aggregation. In contrast, interactions of agrin with binding proteins on the 
      muscle surface harbouring different specificities such as alpha-dystroglycan do 
      not seem to be necessary for this process.
FAU - Hopf, C
AU  - Hopf C
AD  - Max-Planck-Institut fur Entwicklungsbiologie, Abteilung Biochemie, Tubingen, 
      Germany.
FAU - Hoch, W
AU  - Hoch W
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Eur J Biochem
JT  - European journal of biochemistry
JID - 0107600
RN  - 0 (Agrin)
RN  - 0 (Receptors, Cholinergic)
RN  - 42HK56048U (Tyrosine)
RN  - EC 2.7.10.1 (MUSK protein, human)
RN  - EC 2.7.10.1 (Receptor Protein-Tyrosine Kinases)
SB  - IM
MH  - Agrin/*metabolism
MH  - Animals
MH  - COS Cells/enzymology
MH  - Chlorocebus aethiops
MH  - Neuromuscular Junction/*enzymology
MH  - Phosphorylation
MH  - Receptor Protein-Tyrosine Kinases/chemistry/immunology/*metabolism
MH  - Receptors, Cholinergic/*metabolism
MH  - Tyrosine/chemistry
EDAT- 1998/07/08 00:00
MHDA- 1998/07/08 00:01
CRDT- 1998/07/08 00:00
PHST- 1998/07/08 00:00 [pubmed]
PHST- 1998/07/08 00:01 [medline]
PHST- 1998/07/08 00:00 [entrez]
AID - 10.1046/j.1432-1327.1998.2530382.x [doi]
PST - ppublish
SO  - Eur J Biochem. 1998 Apr 15;253(2):382-9. doi: 10.1046/j.1432-1327.1998.2530382.x.