PMID- 29122950
OWN - NLM
STAT- MEDLINE
DCOM- 20190130
LR  - 20190130
IS  - 1477-9145 (Electronic)
IS  - 0022-0949 (Linking)
VI  - 221
IP  - Pt 2
DP  - 2018 Jan 30
TI  - Myosin phosphorylation potentiates steady-state work output without altering 
      contractile economy of mouse fast skeletal muscles.
LID - jeb167742 [pii]
LID - 10.1242/jeb.167742 [doi]
AB  - Skeletal myosin light chain kinase (skMLCK)-catalyzed phosphorylation of the 
      myosin regulatory light chain (RLC) increases (i.e. potentiates) mechanical work 
      output of fast skeletal muscle. The influence of this event on contractile 
      economy (i.e. energy cost/work performed) remains controversial, however. Our 
      purpose was to quantify contractile economy of potentiated extensor digitorum 
      longus (EDL) muscles from mouse skeletal muscles with (wild-type, WT) and without 
      (skMLCK ablated, skMLCK(-/-)) the ability to phosphorylate the RLC. Contractile 
      economy was calculated as the ratio of total work performed to high-energy 
      phosphate consumption (HEPC) during a period of repeated isovelocity contractions 
      that followed a potentiating stimulus (PS). Consistent with genotype, the PS 
      increased RLC phosphorylation measured during, before and after isovelocity 
      contractions in WT but not in skMLCK(-/-) muscles (i.e. 0.65 and 0.05 mol 
      phosphate mol(-1) RLC, respectively). In addition, although the PS enhanced work 
      during repeated isovelocity contractions in both genotypes, the increase was 
      significantly greater in WT than in skMLCK(-/-) muscles (1.51+/-0.03 versus 
      1.10+/-0.05, respectively; all data P<0.05, n=8). Interestingly, the HEPC 
      determined during repeated isovelocity contractions was statistically similar 
      between genotypes at 19.03+/-3.37 and 16.02+/-3.41 mumol P; respectively (P<0.27). As 
      a result, despite performing significantly more work, the contractile economy 
      calculated for WT muscles was similar to that calculated for skMLCK(-/-) muscles 
      (i.e. 5.74+/-0.67 and 4.61+/-0.71 J kg(-1) mumol(-1) P, respectively (P<0.27). In 
      conclusion, our results support the notion that myosin RLC phosphorylation 
      enhances dynamic contractile function of mouse fast skeletal muscle but does so 
      without decreasing contractile economy.
CI  - (c) 2018. Published by The Company of Biologists Ltd.
FAU - Gittings, William
AU  - Gittings W
AD  - Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock 
      University, St Catharines, ON L2S 3A1, Canada.
FAU - Bunda, Jordan
AU  - Bunda J
AUID- ORCID: 0000-0001-9213-8709
AD  - Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock 
      University, St Catharines, ON L2S 3A1, Canada.
FAU - Vandenboom, Rene
AU  - Vandenboom R
AUID- ORCID: 0000-0002-6838-6419
AD  - Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock 
      University, St Catharines, ON L2S 3A1, Canada rvandenboom@brocku.ca.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20180130
PL  - England
TA  - J Exp Biol
JT  - The Journal of experimental biology
JID - 0243705
RN  - EC 3.6.4.1 (Myosins)
SB  - IM
MH  - Animals
MH  - Mice
MH  - Mice, Inbred C57BL
MH  - Muscle Contraction/*physiology
MH  - Muscle, Skeletal/*physiology
MH  - Myosins/*metabolism
MH  - Phosphorylation
OTO - NOTNLM
OT  - Economy
OT  - Energetics
OT  - Myosin light chain kinase knockout
OT  - Potentiation
OT  - Regulatory light chain
COIS- Competing interestsThe authors declare no competing or financial interests.
EDAT- 2017/11/11 06:00
MHDA- 2019/01/31 06:00
CRDT- 2017/11/11 06:00
PHST- 2017/08/04 00:00 [received]
PHST- 2017/10/28 00:00 [accepted]
PHST- 2017/11/11 06:00 [pubmed]
PHST- 2019/01/31 06:00 [medline]
PHST- 2017/11/11 06:00 [entrez]
AID - jeb.167742 [pii]
AID - 10.1242/jeb.167742 [doi]
PST - epublish
SO  - J Exp Biol. 2018 Jan 30;221(Pt 2):jeb167742. doi: 10.1242/jeb.167742.