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Alpha-catalytic subunits of 5'AMP-activated protein kinase display fiber-specific expression and are upregulated by chronic low-frequency stimulation in rat muscle.
Am J Physiol Regul Integr Comp Physiol. 2007 Sep; 293(3):R1325-34.AJ

Abstract

5'-AMP-activated protein kinase (AMPK) signaling initiates adaptive changes in skeletal muscle fibers that restore homeostatic energy balance. The purpose of this investigation was to examine, in rats, the fiber-type protein expression patterns of the alpha-catalytic subunit isoforms in various skeletal muscles, and changes in their respective contents within the tibialis anterior (TA) after chronic low-frequency electrical stimulation (CLFS; 10 Hz, 10 h daily), applied for 4 +/- 1.2 or 25 +/- 4.8 days. Immunocytochemical staining of soleus (SOL) and medial gastrocnemius (MG) showed that 86 +/- 4.1 to 97 +/- 1.4% of type IIA fibers stained for both the alpha1- and alpha2-isoforms progressively decreased to 63 +/- 12.2% of type IID/X and 9 +/- 2.4% of IIB fibers. 39 +/- 11.4% of IID/X and 83 +/- 7.9% of IIB fibers expressed only the alpha2 isoform in the MG, much of which was localized within nuclei. alpha1 and alpha2 contents, assessed by immunoblot, were lowest in the white gastrocnemius [WG; 80% myosin heavy chain (MHC) IIb; 20% MHCIId/x]. Compared with the WG, alpha1 content was 1.6 +/- 0.08 (P < 0.001) and 1.8 +/- 0.04 (P < 0.0001)-fold greater in the red gastrocnemius (RG: 13%, MHCIIa) and SOL (21%, MHCIIa), respectively, and increased in proportion to MHCIIa content. Similarly, alpha2 content was 1.4 +/- 0.10 (P < 0.02) and 1.5 +/- 0.07 (P < 0.001)-fold greater in RG and SOL compared with WG. CLFS induced 1.43 +/- 0.13 (P < 0.007) and 1.33 +/- 0.08 (P < 0.009)-fold increases in the alpha1 and alpha2 contents of the TA and coincided with the transition of faster type IIB and IID/X fibers toward IIA fibers. These findings indicate that fiber types differ with regard to their capacity for AMPK signaling and that this potential is increased by CLFS.

Authors+Show Affiliations

Faculty of Physical Education and Recreation and The Centre for Neuroscience, Faculty of Medicine & Dentistry, University of Alberta, E-417 Van Vliet Centre, Edmonton, Alberta, Canada. tputman@ualberta.caNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17553841

Citation

Putman, Charles T., et al. "Alpha-catalytic Subunits of 5'AMP-activated Protein Kinase Display Fiber-specific Expression and Are Upregulated By Chronic Low-frequency Stimulation in Rat Muscle." American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, vol. 293, no. 3, 2007, pp. R1325-34.
Putman CT, Martins KJ, Gallo ME, et al. Alpha-catalytic subunits of 5'AMP-activated protein kinase display fiber-specific expression and are upregulated by chronic low-frequency stimulation in rat muscle. Am J Physiol Regul Integr Comp Physiol. 2007;293(3):R1325-34.
Putman, C. T., Martins, K. J., Gallo, M. E., Lopaschuk, G. D., Pearcey, J. A., MacLean, I. M., Saranchuk, R. J., & Pette, D. (2007). Alpha-catalytic subunits of 5'AMP-activated protein kinase display fiber-specific expression and are upregulated by chronic low-frequency stimulation in rat muscle. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 293(3), R1325-34.
Putman CT, et al. Alpha-catalytic Subunits of 5'AMP-activated Protein Kinase Display Fiber-specific Expression and Are Upregulated By Chronic Low-frequency Stimulation in Rat Muscle. Am J Physiol Regul Integr Comp Physiol. 2007;293(3):R1325-34. PubMed PMID: 17553841.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Alpha-catalytic subunits of 5'AMP-activated protein kinase display fiber-specific expression and are upregulated by chronic low-frequency stimulation in rat muscle. AU - Putman,Charles T, AU - Martins,Karen J B, AU - Gallo,Maria E, AU - Lopaschuk,Gary D, AU - Pearcey,Jean A, AU - MacLean,Ian M, AU - Saranchuk,Ryan J, AU - Pette,Dirk, Y1 - 2007/06/06/ PY - 2007/6/8/pubmed PY - 2007/10/18/medline PY - 2007/6/8/entrez SP - R1325 EP - 34 JF - American journal of physiology. Regulatory, integrative and comparative physiology JO - Am J Physiol Regul Integr Comp Physiol VL - 293 IS - 3 N2 - 5'-AMP-activated protein kinase (AMPK) signaling initiates adaptive changes in skeletal muscle fibers that restore homeostatic energy balance. The purpose of this investigation was to examine, in rats, the fiber-type protein expression patterns of the alpha-catalytic subunit isoforms in various skeletal muscles, and changes in their respective contents within the tibialis anterior (TA) after chronic low-frequency electrical stimulation (CLFS; 10 Hz, 10 h daily), applied for 4 +/- 1.2 or 25 +/- 4.8 days. Immunocytochemical staining of soleus (SOL) and medial gastrocnemius (MG) showed that 86 +/- 4.1 to 97 +/- 1.4% of type IIA fibers stained for both the alpha1- and alpha2-isoforms progressively decreased to 63 +/- 12.2% of type IID/X and 9 +/- 2.4% of IIB fibers. 39 +/- 11.4% of IID/X and 83 +/- 7.9% of IIB fibers expressed only the alpha2 isoform in the MG, much of which was localized within nuclei. alpha1 and alpha2 contents, assessed by immunoblot, were lowest in the white gastrocnemius [WG; 80% myosin heavy chain (MHC) IIb; 20% MHCIId/x]. Compared with the WG, alpha1 content was 1.6 +/- 0.08 (P < 0.001) and 1.8 +/- 0.04 (P < 0.0001)-fold greater in the red gastrocnemius (RG: 13%, MHCIIa) and SOL (21%, MHCIIa), respectively, and increased in proportion to MHCIIa content. Similarly, alpha2 content was 1.4 +/- 0.10 (P < 0.02) and 1.5 +/- 0.07 (P < 0.001)-fold greater in RG and SOL compared with WG. CLFS induced 1.43 +/- 0.13 (P < 0.007) and 1.33 +/- 0.08 (P < 0.009)-fold increases in the alpha1 and alpha2 contents of the TA and coincided with the transition of faster type IIB and IID/X fibers toward IIA fibers. These findings indicate that fiber types differ with regard to their capacity for AMPK signaling and that this potential is increased by CLFS. SN - 0363-6119 UR - https://www.unboundmedicine.com/medline/citation/17553841/Alpha_catalytic_subunits_of_5'AMP_activated_protein_kinase_display_fiber_specific_expression_and_are_upregulated_by_chronic_low_frequency_stimulation_in_rat_muscle_ L2 - https://journals.physiology.org/doi/10.1152/ajpregu.00609.2006?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -