TY - JOUR
T1 - O-fucosylation of muscle agrin determines its ability to cluster acetylcholine receptors
AU - Kim, Mi Lyang
AU - Chandrasekharan, Kumaran
AU - Glass, Matthew
AU - Shi, Shaolin
AU - Stahl, Mark C.
AU - Kaspar, Brian
AU - Stanley, Pamela
AU - Martin, Paul T.
N1 - Funding Information:
This work was supported by NCI grant RO1 95022 to P.S. and NIH grants RO1 AR050202 and RO1 AR047922 to P.T.M. We thank Jihua Chen (Albert Einstein College of Medicine) for the Chinese hamster Pofut1 cDNA sequence, K. Reed Clark (The Research Institute at Nationwide Children's Hospital) for Adenovirus-GFP, Bing Xia (University of California, San Diego) for help with preliminary experiments, and Neha Singhal (The Research Institute at Nationwide Children's Hospital) for production of Pofut1 antibodies.
PY - 2008/10/29
Y1 - 2008/10/29
N2 - Protein O-fucosyltransferase 1 (Pofut1) transfers fucose to serine or threonine on proteins, including Notch receptors, that contain EGF repeats with a particular consensus sequence. Here we demonstrate that agrin is O-fucosylated in a Pofut1-dependent manner, and that this glycosylation can regulate agrin function. Fucosylation of recombinant C45 agrin, both active (neural, z8) and inactive (muscle, z0) splice forms, was eliminated when agrin was overexpressed in Pofut1-deficient cells or by mutation of a consensus site for Pofut1 fucosylation (serine 1726 in the EGF4 domain). Loss of O-fucosylation caused a gain of function for muscle agrin such that it stimulated AChR clustering and MuSK phosphorylation in cultured myotubes at levels normally only found with the neural splice form. Deletion of Pofut1 in cultured primary myotubes and in adult skeletal muscle increased AChR aggregation. In addition, Pofut1 gene and protein expression and Pofut1 activity of the EGF4 domain of agrin were modulated during neuromuscular development. These data are consistent with a role for Pofut1 in AChR aggregation during synaptogenesis via the regulation of the synaptogenic activity of muscle agrin.
AB - Protein O-fucosyltransferase 1 (Pofut1) transfers fucose to serine or threonine on proteins, including Notch receptors, that contain EGF repeats with a particular consensus sequence. Here we demonstrate that agrin is O-fucosylated in a Pofut1-dependent manner, and that this glycosylation can regulate agrin function. Fucosylation of recombinant C45 agrin, both active (neural, z8) and inactive (muscle, z0) splice forms, was eliminated when agrin was overexpressed in Pofut1-deficient cells or by mutation of a consensus site for Pofut1 fucosylation (serine 1726 in the EGF4 domain). Loss of O-fucosylation caused a gain of function for muscle agrin such that it stimulated AChR clustering and MuSK phosphorylation in cultured myotubes at levels normally only found with the neural splice form. Deletion of Pofut1 in cultured primary myotubes and in adult skeletal muscle increased AChR aggregation. In addition, Pofut1 gene and protein expression and Pofut1 activity of the EGF4 domain of agrin were modulated during neuromuscular development. These data are consistent with a role for Pofut1 in AChR aggregation during synaptogenesis via the regulation of the synaptogenic activity of muscle agrin.
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U2 - 10.1016/j.mcn.2008.07.026
DO - 10.1016/j.mcn.2008.07.026
M3 - Article
C2 - 18775496
AN - SCOPUS:53649090611
SN - 1044-7431
VL - 39
SP - 452
EP - 464
JO - Molecular and Cellular Neuroscience
JF - Molecular and Cellular Neuroscience
IS - 3
ER -