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The beta‐isoform of neuronal nitric oxide synthase (nNOS) lacking the PDZ domain is localized at the sarcolemma
Author(s) -
Baum Oliver,
Schläppi Simon,
Huber-Abel Felicitas A.,
Weichert Alexander,
Hoppeler Hans,
Zakrzewicz Andreas
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.09.016
Subject(s) - gene isoform , sarcolemma , pdz domain , nitric oxide synthase , chemistry , colocalization , biochemistry , microbiology and biotechnology , epitope , immunoprecipitation , alpha (finance) , immunohistochemistry , antibody , biology , enzyme , membrane , gene , immunology , medicine , construct validity , nursing , patient satisfaction
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.