| First Author | Basu S | Year | 2015 |
| Journal | Mol Biol Cell | Volume | 26 |
| Issue | 5 | Pages | 938-51 |
| PubMed ID | 25589673 | Mgi Jnum | J:311786 |
| Mgi Id | MGI:6780543 | Doi | 10.1091/mbc.E14-06-1158 |
| Citation | Basu S, et al. (2015) CLASP2-dependent microtubule capture at the neuromuscular junction membrane requires LL5beta and actin for focal delivery of acetylcholine receptor vesicles. Mol Biol Cell 26(5):938-51 |
| abstractText | A hallmark of the neuromuscular junction (NMJ) is the high density of acetylcholine receptors (AChRs) in the postsynaptic muscle membrane. The postsynaptic apparatus of the NMJ is organized by agrin secreted from motor neurons. The mechanisms that underlie the focal delivery of AChRs to the adult NMJ are not yet understood in detail. We previously showed that microtubule (MT) capture by the plus end-tracking protein CLASP2 regulates AChR density at agrin-induced AChR clusters in cultured myotubes via PI3 kinase acting through GSK3beta. Here we show that knockdown of the CLASP2-interaction partner LL5beta by RNAi and forced expression of a CLASP2 fragment blocking the CLASP2/LL5beta interaction inhibit microtubule capture. The same treatments impair focal vesicle delivery to the clusters. Consistent with these findings, knockdown of LL5beta at the NMJ in vivo reduces the density and insertion of AChRs into the postsynaptic membrane. MT capture and focal vesicle delivery to agrin-induced AChR clusters are also inhibited by microtubule- and actin-depolymerizing drugs, invoking both cytoskeletal systems in MT capture and in the fusion of AChR vesicles with the cluster membrane. Combined our data identify a transport system, organized by agrin through PI3 kinase, GSK3beta, CLASP2, and LL5beta, for precise delivery of AChR vesicles from the subsynaptic nuclei to the overlying synaptic membrane. |
