Dual-specificity phosphatase 4 is upregulated during skeletal muscle atrophy and modulates extracellular signal-regulated kinase activity
Document Type
Article
Publication Date
4-1-2019
Abstract
Skeletal muscle atrophy results from disparate physiological conditions, including denervation, corticosteroid treatment, and aging. The purpose of this study was to describe and characterize the function of dual-specificity phosphatase 4 (Dusp4) in skeletal muscle after it was found to be induced in response to neurogenic atrophy. Quantitative PCR and Western blot analysis revealed that Dusp4 is expressed during myoblast proliferation but rapidly disappears as muscle cells differentiate. The Dusp4 regulatory region was cloned and found to contain a conserved E-box element that negatively regulates Dusp4 reporter gene activity in response to myogenic regulatory factor expression. In addition, the proximal 3=-untranslated region of Dusp4 acts in an inhibitory manner to repress reporter gene activity as muscle cells progress through the differentiation process. To determine potential function, Dusp4 was fused with green fluorescent protein, expressed in C2C12 cells, and found to localize to the nucleus of proliferating myoblasts. Furthermore, Dusp4 overexpression delayed C2C12 muscle cell differentiation and resulted in repression f a MAP kinase signaling pathway reporter gene. Ectopic expression of a Dusp4 dominant negative mutant blocked muscle cell differentiation and attenuated MAP kinase signaling by preferentially targeting the ERK1/2 branch, but not the p38 branch, of the MAP kinase signaling cascade in skeletal muscle cells. The findings presented in this study provide the first description of Dusp4 in skeletal muscle and suggest that Dusp4 may play an important role in the regulation of muscle cell differentiation by regulating MAP kinase signaling.
Publication Title
American Journal of Physiology - Cell Physiology
Volume
316
Issue
4
First Page
C567
Last Page
C581
Digital Object Identifier (DOI)
10.1152/ajpcell.00234.2018
PubMed ID
30758994
ISSN
03636143
E-ISSN
15221563
Citation Information
Haddock, A.N., Labuzan, S.A., Haynes, A.E., Hayes, C.B., Kakareka, K.M., Waddell, D.S. (2019) Dual-specificity Phosphatase 4 is Upregulated During Skeletal Muscle Atrophy and Modulates Extracellular Signal-regulated Kinase Activity. American Journal of Physiology - Cell Physiology, 316(4), C567-C581.