Localization of the membrane-anchored MMP-regulator RECK at the neuromuscular junctions.
Nerve apposition on nicotinic acetylcholine receptor clusters and invagination of the post-synaptic membrane (i.e. secondary fold formation) occur by embryonic day 18.5 at the neuromuscular junctions (NMJs) in mouse skeletal muscles. Finding the molecules expressed at the NMJ at this stage of development may help elucidating how the strong linkage between a nerve terminal and a muscle fiber is established. Immunohistochemical analyses indicated that the membrane-anchored matrix metalloproteinase regulator RECK was enriched at the NMJ in adult skeletal muscles. Confocal and electron microscopy revealed the localization of RECK immunoreactivity in secondary folds and subsynaptic intracellular compartments in muscles. Time course studies indicated that RECK immunoreactivity becomes associated with the NMJ in the diaphragm at around embryonic day 18.5 and thereafter. These findings, together with known properties of RECK, support the hypothesis that RECK participates in NMJ formation and/or maintenance, possibly by protecting extracellular components, such as synaptic basal laminae, from proteolytic degradation.
Kawashima
Satoshi
S
Department of Molecular Oncology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. mnoda@virus.kyoto-u.ac.jp
Imamura
Yukio
Y
Chandana
Ediriweera P S
EP
Noda
Toru
T
Takahashi
Rei
R
Adachi
Eijiro
E
Takahashi
Chiaki
C
Noda
Makoto
M
D000818:Animals; D000831:Animals, Newborn; D004622:Embryo, Mammalian; D058851:GPI-Linked Proteins; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D016253:Microscopy, Immunoelectron / Q000379:methods; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism; D009469:Neuromuscular Junction / Q000378:metabolism* / Q000648:ultrastructure
D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009124:Muscle Proteins; C492025:Reck protein, mouse