Expression of nonmuscle myosin heavy and light chains in smooth muscle

Gaylinn, Bruce D.; Eddinger, Thomas J.; Martino, Paul A.; Monical, Penny L.; Hunt, Donald F.; Murphy, Richard A.

doi:10.1152/ajpcell.1989.257.5.c997

Cited by 66 publications

(46 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4), and we found that tonic contractions were potently inhibited by (Ϫ)blebbistatin. Finally, the amount of nonmuscle myosin II in adult animals is a very small percentage of the total myosin II content (Ͻ15% in swine carotid, Ͻ10% in rat carotid, and Ͻ20% in mouse carotid) (Gaylinn et al, 1989;Eddinger and Murphy, 1991;Eddinger and Wolf, 1993). Although these data cannot prove that nonmuscle myosin II does not contribute to force maintenance, it would seem unlikely that nonmuscle myosin II would be responsible for the maintenance of high stresses in smooth muscles when much larger amounts of smooth muscle myosin II is expressed.…”

Section: Discussionmentioning

confidence: 92%

See 1 more Smart Citation

Potent Inhibition of Arterial Smooth Muscle Tonic Contractions by the Selective Myosin II Inhibitor, Blebbistatin

Eddinger¹,

Meer²,

Miner³

et al. 2006

J Pharmacol Exp Ther

View full text Add to dashboard Cite

Blebbistatin is reported to be a selective and specific small molecule inhibitor of the myosin II isoforms expressed by striated muscles and nonmuscle (IC 50 ϭ 0.5-5 M) but is a poor inhibitor of purified turkey smooth muscle myosin II (IC 50 ϳ80 M). We found that blebbistatin potently (IC 50 ϳ3 M) inhibited the actomyosin ATPase activities of expressed "slow" [smooth muscle myosin IIA (SMA)] and "fast" [smooth muscle myosin IIB (SMB)] smooth muscle myosin II heavy-chain isoforms. Blebbistatin also inhibited the KCl-induced tonic contractions produced by rabbit femoral and renal arteries that express primarily SMA and the weaker tonic contraction produced by the saphenous artery that expresses primarily SMB, with an equivalent potency comparable with that identified for nonmuscle myosin IIA (IC 50 ϳ5 M). In femoral and saphenous arteries, blebbistatin had no effect on unloaded shortening velocity or the tonic increase in myosin light-chain phosphorylation produced by KCl but potently inhibited ␤-escin permeabilized artery contracted with calcium at pCa 5, suggesting that cell signaling events upstream from KCl-induced activation of cross-bridges were unaffected by blebbistatin. It is noteworthy that KCl-induced contractions of chicken gizzard were less potently inhibited (IC 50 ϳ20 M). Adult femoral, renal, and saphenous arteries did not express significant levels of nonmuscle myosin. These data together indicate that blebbistatin is a potent inhibitor of smooth muscle myosin II, supporting the hypothesis that the force-bearing structure responsible for tonic force maintenance in adult mammalian vascular smooth muscle is the cross-bridge formed from the blebbistatin-dependent interaction between actin and smooth muscle myosin II.

show abstract

Section: Discussionmentioning

confidence: 92%

“…Nonmuscle myosin IIA (NMA)-and NMB-specific nonmuscle-specific antibodies were obtained from Covance (Berkeley, CA). Western immunoblots were reacted as reported previously (Gaylinn et al, 1989).…”

Section: Methodsmentioning

confidence: 99%

Potent Inhibition of Arterial Smooth Muscle Tonic Contractions by the Selective Myosin II Inhibitor, Blebbistatin

Eddinger¹,

Meer²,

Miner³

et al. 2006

J Pharmacol Exp Ther

View full text Add to dashboard Cite

show abstract

“…These essential MLC isoforms are characterized by their isoelectric points; LC17a is the more acidic of the two species (Hasegawa and Morita 1992; see Eddinger et al 2000 for nomenclature). Lastly, two different genes code for nonmuscle (NM) and smooth muscle (SM) LC20, which are identical in size but differ at 11 residues (Taubman et al 1987;Kumar et al 1989;Gaylinn et al 1989). The more basic of these two isoforms is characterized as the SM isoform, with the more acidic being the NM variety (Bárány and Bárány 1996).…”

mentioning

confidence: 99%

Smooth Muscle Myosin Heavy Chain Isoform Distribution in the Swine Stomach

Parisi

Eddinger

2002

J Histochem Cytochem.

View full text Add to dashboard Cite

S U M M A R YTo evaluate the distribution of smooth muscle myosin heavy chain isoforms (SMB, with head insert), we examined frozen sections from the various regions of swine stomachs using isoform-specific antibodies. We previously reported variable SMB myosin heavy chain (MHC) expression in stomach cells that correlates with unloaded shortening velocities. This is consistent with the generalization of tonic fundic muscle having low expression and phasic antral muscle having high expression of the SMB MHC isoform. Using immunohistochemistry (IHC), we show a progression of the SMB MHC from very low immunoreactivity in the fundus to very intense immunoreactivity in the antrum. In the body, the average level of SMB MHC immunoreactivity lies between that of the antrum and fundus. Intercellular heterogeneity was observed in all stomach regions to a similar extent. However, the intercellular range in SMB MHC immunoreactivity decreases from fundus to antrum.

show abstract

“…A third possibility is that a small amount of nonmuscle myosin may be present in differentiated smooth muscle cells, as previously reported. 40 Further cytological studies aimed at localizing various myosin types are important for a better understanding of the level of differentiation of the muscle cells in the arterial media and the relevance of their response in pathological processes. It has been shown recently that the hypertrophy of urinary bladder smooth muscle is associated with an alteration of the ratio of SM-1 to SM-2 in favor of SM-1.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of arterial myosin in experimental renal hypertension in the dog.

et al. 1993

View full text Add to dashboard Cite

We compared myosin samples isolated from iliac-femoral arteries of control and renal (stenosis) hypertensive dogs to determine the effects of increased blood pressure on the characteristics of the myosin. The ratio of 204-kd (SM-1) to 200 -kd (SM-2) myosin heavy chains was approximately 1:0.75 for myosin from the iliac-femoral artery of normotensive dogs. This was not altered significantly in response to hypertension. Both SM-1 and SM-2 myosin heavy chains cross-reacted with antibody against smooth muscle myosin on Western blot analysis. In addition to these heavy chains, purified myosin from both groups showed a very faint protein band slightly below the 200-kd myosin heavy chain on electrophoresis on a highly porous sodium dodecyl sulfate-polyacrylamide gel. This protein band cross-reacted with antibody against nonmuscle myosin but not with smooth muscle myosin antibody. The 20-and 17-kd light chains of myosin isolated from normotensive and hypertensive dogs gave similar results on isoelectric focusing. Peptide maps of tryptic digests of heavy chains revealed both quantitative and qualitative differences. The Ca "-activated myosin ATPase activity measured in high salt (0.5 mol/L KC1) was similar for myosin from both groups, whereas the potassium (ethylenedinitrilo)tetraacetic acid-stimulated ATPase of myosin from hypertensive animals was higher than that from normotensive animals. The actin-activated ATPase activities of the myosin from hypertensive animals was also higher than that of the myosin isolated from normotensive artery (0.11 ±0.007 and 0.213±0.008 fimo\ Pi per milligram per minute, respectively, for normotensive and hypertensive). These studies indicate that the structural and functional properties of myosin in a muscular artery are altered in hypertensive dogs. Adaptive changes in the vascular smooth muscle are observed with primary hypertension in humans and in spontaneously hypertensive rats.5 Increased thickness of the arterial media with a decrease in lumen diameter has been observed in a variety of hypertensive models.5 " 7 The increase in the wall thickness associated with hypertension is accompanied by an increase in smooth muscle mass. 7 The growth response of cells in the

show abstract

Expression of nonmuscle myosin heavy and light chains in smooth muscle

Cited by 66 publications

References 31 publications

Potent Inhibition of Arterial Smooth Muscle Tonic Contractions by the Selective Myosin II Inhibitor, Blebbistatin

Potent Inhibition of Arterial Smooth Muscle Tonic Contractions by the Selective Myosin II Inhibitor, Blebbistatin

Smooth Muscle Myosin Heavy Chain Isoform Distribution in the Swine Stomach

Characteristics of arterial myosin in experimental renal hypertension in the dog.

Contact Info

Product

Resources

About