Abstract
Comparison of mammalian cardiac α- and β-myosin heavy chain isoforms reveals 93% identity. To date, genetic methodologies have effected only minor switches in the mammalian cardiac myosin isoforms. Using cardiac-specific transgenesis, we have now obtained major myosin isoform shifts and/or replacements. Clusters of non-identical amino acids are found in functionally important regions, i.e. the surface loops 1 and 2, suggesting that these structures may regulate isoform-specific characteristics. Loop 1 alters filament sliding velocity, whereas Loop 2 modulates actin-activated ATPase rate in Dictyostelium myosin, but this remains untested in mammalian cardiac myosins. α → β isoform switches were engineered into mouse hearts via transgenesis. To assess the structural basis of isoform diversity, chimeric myosins in which the sequences of either Loop 1 + Loop 2 or Loop 2 of α-myosin were exchanged for those of β-myosin were expressed in vivo. 2-fold differences in filament sliding velocity and ATPase activity were found between the two isoforms. Filament sliding velocity of the Loop 1 + Loop 2 chimera and the ATPase activities of both loop chimeras were not significantly different compared with α-myosin. In mouse cardiac isoforms, myosin functionality does not depend on Loop 1 or Loop 2 sequences and must lie partially in other non-homologous residues.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 17466-17474 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 278 |
| Issue number | 19 |
| DOIs | |
| State | Published - May 9 2003 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Analysis of myosin heavy chain functionality in the heart. / Krenz, Maike; Sanbe, Atsushi; Bouyer-Dalloz, Florence; Gulick, James; Klevitsky, Raisa; Hewett, Timothy; Osinska, Hanna E.; Lorenz, John N.; Brosseau, Christine; Federico, Andrea; Alpert, Norman R.; Warshaw, David M.; Perryman, M. Benjamin; Helmke, Steve M.; Robbins, Jeffrey.
In: Journal of Biological Chemistry, Vol. 278, No. 19, 09.05.2003, p. 17466-17474.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Analysis of myosin heavy chain functionality in the heart
AU - Krenz, Maike
AU - Sanbe, Atsushi
AU - Bouyer-Dalloz, Florence
AU - Gulick, James
AU - Klevitsky, Raisa
AU - Hewett, Timothy
AU - Osinska, Hanna E.
AU - Lorenz, John N.
AU - Brosseau, Christine
AU - Federico, Andrea
AU - Alpert, Norman R.
AU - Warshaw, David M.
AU - Perryman, M. Benjamin
AU - Helmke, Steve M.
AU - Robbins, Jeffrey
PY - 2003/5/9
Y1 - 2003/5/9
N2 - Comparison of mammalian cardiac α- and β-myosin heavy chain isoforms reveals 93% identity. To date, genetic methodologies have effected only minor switches in the mammalian cardiac myosin isoforms. Using cardiac-specific transgenesis, we have now obtained major myosin isoform shifts and/or replacements. Clusters of non-identical amino acids are found in functionally important regions, i.e. the surface loops 1 and 2, suggesting that these structures may regulate isoform-specific characteristics. Loop 1 alters filament sliding velocity, whereas Loop 2 modulates actin-activated ATPase rate in Dictyostelium myosin, but this remains untested in mammalian cardiac myosins. α → β isoform switches were engineered into mouse hearts via transgenesis. To assess the structural basis of isoform diversity, chimeric myosins in which the sequences of either Loop 1 + Loop 2 or Loop 2 of α-myosin were exchanged for those of β-myosin were expressed in vivo. 2-fold differences in filament sliding velocity and ATPase activity were found between the two isoforms. Filament sliding velocity of the Loop 1 + Loop 2 chimera and the ATPase activities of both loop chimeras were not significantly different compared with α-myosin. In mouse cardiac isoforms, myosin functionality does not depend on Loop 1 or Loop 2 sequences and must lie partially in other non-homologous residues.
AB - Comparison of mammalian cardiac α- and β-myosin heavy chain isoforms reveals 93% identity. To date, genetic methodologies have effected only minor switches in the mammalian cardiac myosin isoforms. Using cardiac-specific transgenesis, we have now obtained major myosin isoform shifts and/or replacements. Clusters of non-identical amino acids are found in functionally important regions, i.e. the surface loops 1 and 2, suggesting that these structures may regulate isoform-specific characteristics. Loop 1 alters filament sliding velocity, whereas Loop 2 modulates actin-activated ATPase rate in Dictyostelium myosin, but this remains untested in mammalian cardiac myosins. α → β isoform switches were engineered into mouse hearts via transgenesis. To assess the structural basis of isoform diversity, chimeric myosins in which the sequences of either Loop 1 + Loop 2 or Loop 2 of α-myosin were exchanged for those of β-myosin were expressed in vivo. 2-fold differences in filament sliding velocity and ATPase activity were found between the two isoforms. Filament sliding velocity of the Loop 1 + Loop 2 chimera and the ATPase activities of both loop chimeras were not significantly different compared with α-myosin. In mouse cardiac isoforms, myosin functionality does not depend on Loop 1 or Loop 2 sequences and must lie partially in other non-homologous residues.
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U2 - 10.1074/jbc.M210804200
DO - 10.1074/jbc.M210804200
M3 - Article
VL - 278
SP - 17466
EP - 17474
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 19
ER -