PMID- 29361581
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 improves contractile economy of mouse fast skeletal muscle 
      during staircase potentiation.
LID - jeb167718 [pii]
LID - 10.1242/jeb.167718 [doi]
AB  - Phosphorylation of the myosin regulatory light chain (RLC) by skeletal myosin 
      light chain kinase (skMLCK) potentiates rodent fast twitch muscle but is an 
      ATP-requiring process. Our objective was to investigate the effect of 
      skMLCK-catalyzed RLC phosphorylation on the energetic cost of contraction and the 
      contractile economy (ratio of mechanical output to metabolic input) of mouse fast 
      twitch muscle in vitro (25 degrees C). To this end, extensor digitorum longus (EDL) 
      muscles from wild-type (WT) and from skMLCK-devoid (skMLCK(-/-)) mice were 
      subjected to repetitive low-frequency stimulation (10 Hz for 15 s) to produce 
      staircase potentiation of isometric twitch force, after which muscles were quick 
      frozen for determination of high-energy phosphate consumption (HEPC). During 
      stimulation, WT muscles displayed significant potentiation of isometric twitch 
      force while skMLCK(-/-) muscles did not (i.e. 23% versus 5% change, 
      respectively). Consistent with this, RLC phosphorylation was increased  approximately 3.5-fold 
      from the unstimulated control value in WT but not in skMLCK(-/-) muscles. Despite 
      these differences, the HEPC of WT muscles was not greater than that of 
      skMLCK(-/-) muscles. As a result of the increased contractile output relative to 
      HEPC, the calculated contractile economy of WT muscles was greater than that of 
      skMLCK(-/-) muscles. Thus, our results suggest that skMLCK-catalyzed 
      phosphorylation of the myosin RLC increases the contractile economy of WT mouse 
      EDL muscle compared with skMLCK(-/-) muscles without RLC phosphorylation.
CI  - (c) 2018. Published by The Company of Biologists Ltd.
FAU - Bunda, Jordan
AU  - Bunda J
AD  - Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock 
      University, St Catharines, ON L2S 3A1, Canada.
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 - 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  - Energetics
OT  - Isometric twitch
OT  - Myosin light chain kinase
OT  - Regulatory light chain
COIS- Competing interestsThe authors declare no competing or financial interests.
EDAT- 2018/01/24 06:00
MHDA- 2019/01/31 06:00
CRDT- 2018/01/24 06:00
PHST- 2017/08/04 00:00 [received]
PHST- 2017/12/31 00:00 [accepted]
PHST- 2018/01/24 06:00 [pubmed]
PHST- 2019/01/31 06:00 [medline]
PHST- 2018/01/24 06:00 [entrez]
AID - jeb.167718 [pii]
AID - 10.1242/jeb.167718 [doi]
PST - epublish
SO  - J Exp Biol. 2018 Jan 30;221(Pt 2):jeb167718. doi: 10.1242/jeb.167718.