Faculty Collaboration Database

Single rabbit stomach smooth muscle cell myosin heavy chain SMB expression and shortening velocity. Am J Physiol Cell Physiol 2001 Feb;280(2):C309-16

Date

02/24/2001

Pubmed ID

11208526

DOI

10.1152/ajpcell.2001.280.2.C309

Scopus ID

2-s2.0-0035024573 (requires institutional sign-in at Scopus site)   36 Citations

Abstract

Isolated single smooth muscle cells (SMCs) from different regions of the rabbit stomach were used to determine a possible correlation between unloaded shortening velocity and smooth muscle (SM) myosin heavy chain (MHC) S1 head isoform composition (SMA, no head insert; SMB, with head insert). alpha-Toxin-permeabilized isolated single cells were maximally activated to measure unloaded shortening velocity and subsequently used in an RT-PCR reaction to determine the SMA/SMB content of the same cell. SM MHC SMA and SMB isoforms are uniquely distributed in the stomach with cells from the fundic region expressing little SMB (38.1 +/- 7.3% SMB; n = 16); cells from the antrum express primarily SMB (94.9 +/- 1.0% SMB; n = 16). Mean fundic cell unloaded shortening velocity was 0.014 +/- 0.002 cell lengths/s compared with 0.036 +/- 0.002 for the antrum cells. Unloaded shortening velocity in these cells was significantly correlated with their percent SMB expression (r2 = 0.58). Resting cell length does not correlate with the percent SMB expression (n = 32 cells). Previously published assays of purified or expressed SMA and SMB heavy meromyosin show a twofold difference in actin filament sliding speed in in vitro motility assays. Extrapolation of our data to 0-100% SMB would give a 10-fold range of shortening velocity, which is closer to the approximately 20-fold range reported from various SM tissues. This suggests that mechanisms in addition to the MHC S1 head isoforms regulate shortening velocity.

Author List

Eddinger TJ, Meer DP

Author

Thomas Eddinger PhD Bioological Sciences in the Biology department at Marquette University

MESH terms used to index this publication - Major topics in bold

Animals
Autoantigens
Gastric Mucosa
Muscle Contraction
Muscle, Smooth
Myosin Heavy Chains
Protein Isoforms
RNA, Messenger
Rabbits
Ribonucleoproteins, Small Nuclear
Stomach