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The mERG1a channel modulates skeletal muscle MuRF1 , but not MAFbx , expression
Author(s) -
Pond Amber L.,
Nedele Carrie,
Wang WenHorng,
Wang Xun,
Walther Claire,
Jaeger Christine,
Bradley Kevin S.,
Du Huahua,
Fujita Naoya,
Hockerman Gregory H.,
Han Kevin M.
Publication year - 2014
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23924
Subject(s) - ubiquitin ligase , muscle atrophy , chemistry , hindlimb , gene expression , dna ligase , gastrocnemius muscle , microbiology and biotechnology , skeletal muscle , messenger rna , complementary dna , endocrinology , medicine , biology , ubiquitin , gene , biochemistry
: We investigated the mechanism by which the MERG1a K + channel increases ubiquitin proteasome proteolysis (UPP). Methods : Hindlimb suspension and electro‐transfer of Merg1a cDNA into mouse gastrocnemius muscles induced atrophy. Results : Atrophic gastrocnemius muscles of hindlimb‐suspended mice express Merg1a , Murf1 , and Mafbx genes. Electrotransfer of Merg1a significantly decreases muscle fiber size (12.6%) and increases UPP E3 ligase Murf1 mRNA (2.1‐fold) and protein (23.7%), but does not affect Mafbx E3 ligase expression. Neither Merg1a ‐induced decreased fiber size nor Merg1a ‐induced increased Murf1 expression is curtailed significantly by coexpression of inactive HR ‐ Foxo3a , a gene encoding a transcription factor known to induce Mafbx expression. Conclusions : The MERG1a K + channel significantly increases expression of Murf1 , but not Mafbx . We explored this expression pattern by expressing inactive Foxo3a and showing that it is not involved in MERG1a‐mediated expression of Murf1 . These findings suggest that MERG1a may not modulate Murf1 expression through the AKT/FOXO pathway. Muscle Nerve 49 :378–388, 2014