title: The beta-isoform of neuronal nitric oxide synthase (nNOS) lacking the PDZ domain is localized at the sarcolemma.
abstract: In skeletal muscles, the expression of neuronal NO synthase (nNOS) isoforms is uncharacterized at the protein level. We therefore conducted epitope mapping with anti-peptide-antibodies. Antibodies specific for the nNOS N-terminus recognized the 160-kDa alpha-isoform. In contrast, antibodies against the middle portion or the C-terminus of nNOS bound additionally to the truncated 140-kDa beta-isoform which lacks the PDZ-domain present in the alpha-isoform. All nNOS immunohistochemical reactivity was confined to the sarcolemma. Consistently, immunoblotting disclosed both nNOS-isoforms to be co-enriched in the membrane-associated fractions. The beta-isoform was co-immunoprecipitated with alpha-isoform antibodies in muscle extracts indicating an association of both nNOS-isoforms to direct the beta-variant to the sarcolemma.
authors.affiliation: Department of Anatomy, University of Bern, Bern, Switzerland. oliver.baum@ana.unibe.ch
authors.forename: Oliver
authors.initials: O
authors.lastname: Baum
authors.forename: Simon
authors.initials: S
authors.lastname: Schläppi
authors.forename: Felicitas A
authors.initials: FA
authors.lastname: Huber-Abel
authors.forename: Alexander
authors.initials: A
authors.lastname: Weichert
authors.forename: Hans
authors.initials: H
authors.lastname: Hoppeler
authors.forename: Andreas
authors.initials: A
authors.lastname: Zakrzewicz
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D007527:Isoenzymes; D051379:Mice; D018345:Mice, Knockout; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology* / Q000235:genetics
chemical_list: D007527:Isoenzymes; D009124:Muscle Proteins; D052248:Nitric Oxide Synthase Type I; C496321:Nos1 protein, mouse