Heavy meromyosin cross-links thin filaments in striated muscle myofibrils

Julian Borejdo, Avraham Oplatka

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Studies of the interaction of proteolytic fragments of myosin with actin filaments in solution have indicated that the two heads of the myosin molecule1 can bind to adjacent subunits in the same actin filament2,3. However, geometrical considerations led Offer and Elliott4 to the conclusion that in the highly ordered filament lattice present in insect flight muscle, tighter binding would occur if the two heads bound to different actin filaments. Indeed, rigidity measurements 5, electron microscope observations6 and superprecipitation experiments7 support the idea that heavy meromyosin (HMM), the double-headed myosin fragment, can cross-link actin filaments in solution. We now provide an experimental demonstration of the cross-linking of thin filaments in muscle by double-headed myosin species. In striated muscle, the thin filament lattice can be stabilized by either the Z-bands or complex formation with myosin. Removal of the Z-bands by a proteolytic enzyme8 or extraction of myosin, leaves the actin-containing I-bands intact. However, if both Z-bands and myosin are removed, the I-bands should disintegrate into single, dispersed, filaments. We found that this could be prevented by preincubation with HMM, but the single -headed HMM subfragment-1 (HMM S-l) was totally ineffective. This strongly suggests that the stabilization by HMM of the filamentous lattice is a result of inter-filament cross-linking.

Original languageEnglish
Pages (from-to)322-323
Number of pages2
JournalNature
Volume291
Issue number5813
DOIs
StatePublished - 1 Dec 1981

Fingerprint

Myosin Subfragments
Striated Muscle
Myofibrils
Myosins
Actin Cytoskeleton
Actins
Myosin Type I
Muscles
Insects
Head
Electrons

Cite this

Borejdo, Julian ; Oplatka, Avraham. / Heavy meromyosin cross-links thin filaments in striated muscle myofibrils. In: Nature. 1981 ; Vol. 291, No. 5813. pp. 322-323.
@article{b5375c14cfb245538b57a9fa7df748a1,
title = "Heavy meromyosin cross-links thin filaments in striated muscle myofibrils",
abstract = "Studies of the interaction of proteolytic fragments of myosin with actin filaments in solution have indicated that the two heads of the myosin molecule1 can bind to adjacent subunits in the same actin filament2,3. However, geometrical considerations led Offer and Elliott4 to the conclusion that in the highly ordered filament lattice present in insect flight muscle, tighter binding would occur if the two heads bound to different actin filaments. Indeed, rigidity measurements 5, electron microscope observations6 and superprecipitation experiments7 support the idea that heavy meromyosin (HMM), the double-headed myosin fragment, can cross-link actin filaments in solution. We now provide an experimental demonstration of the cross-linking of thin filaments in muscle by double-headed myosin species. In striated muscle, the thin filament lattice can be stabilized by either the Z-bands or complex formation with myosin. Removal of the Z-bands by a proteolytic enzyme8 or extraction of myosin, leaves the actin-containing I-bands intact. However, if both Z-bands and myosin are removed, the I-bands should disintegrate into single, dispersed, filaments. We found that this could be prevented by preincubation with HMM, but the single -headed HMM subfragment-1 (HMM S-l) was totally ineffective. This strongly suggests that the stabilization by HMM of the filamentous lattice is a result of inter-filament cross-linking.",
author = "Julian Borejdo and Avraham Oplatka",
year = "1981",
month = "12",
day = "1",
doi = "10.1038/291322a0",
language = "English",
volume = "291",
pages = "322--323",
journal = "Nature",
issn = "0028-0836",
publisher = "Nature Publishing Group",
number = "5813",

}

Heavy meromyosin cross-links thin filaments in striated muscle myofibrils. / Borejdo, Julian; Oplatka, Avraham.

In: Nature, Vol. 291, No. 5813, 01.12.1981, p. 322-323.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Heavy meromyosin cross-links thin filaments in striated muscle myofibrils

AU - Borejdo, Julian

AU - Oplatka, Avraham

PY - 1981/12/1

Y1 - 1981/12/1

N2 - Studies of the interaction of proteolytic fragments of myosin with actin filaments in solution have indicated that the two heads of the myosin molecule1 can bind to adjacent subunits in the same actin filament2,3. However, geometrical considerations led Offer and Elliott4 to the conclusion that in the highly ordered filament lattice present in insect flight muscle, tighter binding would occur if the two heads bound to different actin filaments. Indeed, rigidity measurements 5, electron microscope observations6 and superprecipitation experiments7 support the idea that heavy meromyosin (HMM), the double-headed myosin fragment, can cross-link actin filaments in solution. We now provide an experimental demonstration of the cross-linking of thin filaments in muscle by double-headed myosin species. In striated muscle, the thin filament lattice can be stabilized by either the Z-bands or complex formation with myosin. Removal of the Z-bands by a proteolytic enzyme8 or extraction of myosin, leaves the actin-containing I-bands intact. However, if both Z-bands and myosin are removed, the I-bands should disintegrate into single, dispersed, filaments. We found that this could be prevented by preincubation with HMM, but the single -headed HMM subfragment-1 (HMM S-l) was totally ineffective. This strongly suggests that the stabilization by HMM of the filamentous lattice is a result of inter-filament cross-linking.

AB - Studies of the interaction of proteolytic fragments of myosin with actin filaments in solution have indicated that the two heads of the myosin molecule1 can bind to adjacent subunits in the same actin filament2,3. However, geometrical considerations led Offer and Elliott4 to the conclusion that in the highly ordered filament lattice present in insect flight muscle, tighter binding would occur if the two heads bound to different actin filaments. Indeed, rigidity measurements 5, electron microscope observations6 and superprecipitation experiments7 support the idea that heavy meromyosin (HMM), the double-headed myosin fragment, can cross-link actin filaments in solution. We now provide an experimental demonstration of the cross-linking of thin filaments in muscle by double-headed myosin species. In striated muscle, the thin filament lattice can be stabilized by either the Z-bands or complex formation with myosin. Removal of the Z-bands by a proteolytic enzyme8 or extraction of myosin, leaves the actin-containing I-bands intact. However, if both Z-bands and myosin are removed, the I-bands should disintegrate into single, dispersed, filaments. We found that this could be prevented by preincubation with HMM, but the single -headed HMM subfragment-1 (HMM S-l) was totally ineffective. This strongly suggests that the stabilization by HMM of the filamentous lattice is a result of inter-filament cross-linking.

UR - http://www.scopus.com/inward/record.url?scp=0019448111&partnerID=8YFLogxK

U2 - 10.1038/291322a0

DO - 10.1038/291322a0

M3 - Article

C2 - 7015148

AN - SCOPUS:0019448111

VL - 291

SP - 322

EP - 323

JO - Nature

JF - Nature

SN - 0028-0836

IS - 5813

ER -