title: Restricted localization of proline-rich membrane anchor (PRiMA) of globular form acetylcholinesterase at the neuromuscular junctions--contribution and expression from motor neurons.
abstract: The expression and localization of the proline-rich membrane anchor (PRiMA), an anchoring protein of tetrameric globular form acetylcholinesterase (G(4) AChE), were studied at vertebrate neuromuscular junctions. Both muscle and motor neuron contributed to this synaptic expression pattern. During the development of rat muscles, the expression of PRiMA and AChE(T) and the enzymatic activity increased dramatically; however, the proportion of G(4) AChE decreased. G(4) AChE in muscle was recognized specifically by a PRiMA antibody, indicating the association of this enzyme with PRiMA. Using western blot and ELISA, both PRiMA protein and PRiMA-linked G(4) AChE were found to be present in large amounts in fast-twitch muscle (e.g. tibialis), but in relatively low abundance in slow-twitch muscle (e.g. soleus). These results indicate that the expression level of PRiMA-linked G(4) AChE depends on muscle fiber type. In parallel, the expression of PRiMA, AChE(T) and G(4) AChE also increased in the spinal cord during development. Such expression in motor neurons contributed to the synaptic localization of G(4) AChE. After denervation, the expression of PRiMA, AChE(T) and G(4) AChE decreased markedly in the spinal cord, and in fast- and slow-twitch muscles.
authors.affiliation: Department of Biology and Center for Chinese Medicine, The Hong Kong University of Science and Technology, China.
authors.forename: K Wing
authors.initials: KW
authors.lastname: Leung
authors.forename: Heidi Q
authors.initials: HQ
authors.lastname: Xie
authors.forename: Vicky P
authors.initials: VP
authors.lastname: Chen
authors.forename: Mokka K W
authors.initials: MK
authors.lastname: Mok
authors.forename: Glanice K Y
authors.initials: GK
authors.lastname: Chu
authors.forename: Roy C Y
authors.initials: RC
authors.lastname: Choi
authors.forename: Karl W K
authors.initials: KW
authors.lastname: Tsim
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D017398:Alternative Splicing; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D009046:Motor Neurons / Q000378:metabolism*; D009121:Muscle Denervation; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism; D018482:Muscle, Skeletal / Q000254:growth & development / Q000294:innervation / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000254:growth & development / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C508016:PRiMA1 protein, rat; D000110:Acetylcholinesterase