title: Direct interaction of myosin regulatory light chain with the NMDA receptor.
abstract: NMDA receptors interact with a variety of intracellular proteins at excitatory synapses. In this paper we show that myosin regulatory light chain (RLC) isolated from mouse brain is a NMDA receptor-interacting protein. Myosin RLC bound directly to the C-termini of both NMDA receptor 1 (NR1) and NMDA receptor 2 (NR2) subunits, rendering the interaction of myosin RLC with NMDA receptors distinct from that of calmodulin which is considered a NR1-interacting protein. Myosin RLC co-localized with NR1 in the dendritic spines of isolated hippocampal neurons, and was co-immunoprecipitated from brain extracts in a complex with NR1, NR2A, NR2B, PSD-95, Adaptor protein-2 and myosin II heavy chain. The C0 region of NR1 was necessary and sufficient for binding myosin RLC. Ca2+/calmodulin, but not calmodulin alone, displaced recombinant myosin RLC from the carboxy tail of NR1 indicating that myosin RLC and Ca2+/calmodulin can compete for a common binding site on NR1 in vitro. Myosin RLC is the only known substrate for myosin regulatory light chain kinase, which has recently been shown to modulate NMDA receptor function in isolated hippocampal neurons. Our results suggest that an additional level of NMDA receptor regulation may be mediated via a direct interaction with a light chain of myosin II. Thus, myosin RLC-NMDA receptor interactions may contribute to the contractile and motile forces that are placed upon NMDA receptor subunits during changes associated with synaptic plasticity and neural morphogenesis.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: David
authors.initials: D
authors.lastname: Amparan
authors.forename: Dorina
authors.initials: D
authors.lastname: Avram
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Thomas
authors.forename: Michaela G
authors.initials: MG
authors.lastname: Lindahl
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Gaurav
authors.initials: G
authors.lastname: Bajaj
authors.forename: Jane E
authors.initials: JE
authors.lastname: Ishmael
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000502:physiology; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D002147:Calmodulin / Q000378:metabolism; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D002147:Calmodulin; D018994:Myosin Light Chains; C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate