Postnatal development alters functional compartmentalization of myosin light chain kinase in ovine carotid arteries

Authors

Dane W. Sorensen, Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California.
Elisha R. Injeti, Department of Pharmaceutical Sciences, Cedarville University School of Pharmacy, Cedarville, Ohio.
Luisa Mejia-Aguilar, Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California.
James M. Williams, Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California.Follow
William J. Pearce, Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California.Follow

Document Type

Article

Publication Date

9-1-2021

Publication Title

American journal of physiology. Regulatory, integrative and comparative physiology

E-ISSN

1522-1490

Abstract

The rate-limiting enzyme for vascular contraction, myosin light chain kinase (MLCK), phosphorylates regulatory myosin light chain (MLC) at rates that appear faster despite lower MLCK abundance in fetal compared with adult arteries. This study explores the hypothesis that greater apparent tissue activity of MLCK in fetal arteries is due to age-dependent differences in intracellular distribution of MLCK in relation to MLC. Under optimal conditions, common carotid artery homogenates from nonpregnant adult female sheep and near-term fetuses exhibited similar values of and for MLCK. A custom-designed, computer-controlled apparatus enabled electrical stimulation and high-speed freezing of arterial segments at exactly 0, 1, 2, and 3 s, calculation of in situ rates of MLC phosphorylation, and measurement of time-dependent colocalization between MLCK and MLC. The in situ rate of MLC phosphorylation divided by total MLCK abundance averaged to values 147% greater in fetal (1.06 ± 0.28) than adult (0.43 ± 0.08) arteries, which corresponded, respectively, to 43 ± 10% and 31 ± 3% of the values measured in homogenates. Confocal colocalization analysis revealed in fetal and adult arteries that 33 ± 6% and 20 ± 5% of total MLCK colocalized with pMLC, and that MLCK activation was greater in periluminal than periadventitial regions over the time course of electrical stimulation in both age groups. Together, these results demonstrate that the catalytic activity of MLCK is similar in fetal and adult arteries, but that the fraction of total MLCK in the functional compartment involved in contraction is significantly greater in fetal than adult arteries.

Volume

321

Issue

3

First Page

R441

Last Page

R453

DOI

10.1152/ajpregu.00293.2020

PubMed ID

34318702

Recommended Citation

Sorensen, Dane W.; Injeti, Elisha R.; Mejia-Aguilar, Luisa; Williams, James M.; and Pearce, William J., "Postnatal development alters functional compartmentalization of myosin light chain kinase in ovine carotid arteries" (2021). Loma Linda University Faculty Publications. 319.
https://scholarsrepository.llu.edu/fac_pubs/319