Dimerization Specificity of Adult and Neonatal Chicken Skeletal Muscle Myosin Heavy Chain Rods

Abstract

The dimerization specificity of the recombinantly expressed and purified rod domain of adult and neonatal chicken myosin heavy chain was analyzed using metal chelation chromatography. Our results indicate that full-length adult and neonatal rods preferentially formed homodimers when renatured from an equimolar mixture of the two isoforms denatured in guanidine hydrochloride. The contribution made toward the dimerization specificity by subdomains of the rod has been addressed by making a chimeric protein consisting of the subfragment 2 (S2) region of the adult isoform and the light meromyosin region of the neonatal isoform. The proportion of heterodimers formed in exchange experiments between the chimera and the neonatal and adult rods rose with increase in the sequence homology between the two exchanging proteins. This suggests that multiple regions of the rod domain of chicken MyHC including S2 can contribute toward dimerization specificity.

A Comparative Study of the Involvement of 17 Arabidopsis Myosin Family Members on the Motility of Golgi and Other Organelles

“…Significant motility of eGFP-myosin fusions was also shown previously (Reisen and Hanson, 2007;Sparkes et al, 2008). Heterodimers of myosins were detected in low percentage in different systems; however, it was shown that homodimers are more thermodynamically stable (Dechesne et al, 1987;Kerwin and Bandman, 1991;Singh and Bandman, 2006), and heterodimerization of plant myosins is still to be tested. Interestingly, heterologous interaction between two subdomains of the globular tails GT1 from MYA1 and GT2 from MYA2, XI-C, or XI-K was observed in yeast two-hybrid analysis (Li and Nebenfü hr, 2007).…”

Unravelling the molecular basis of the dominant negative effect of myosin XI tails on P-bodies

“…However, the tail [ 37 , 41 , 51 ] and coiled-coil fragments show little co-localization with actin. Another explanation could be that myosin tails of other isoforms form heterodimers with XI-K, similar to other systems [ 9 , 52 ]. However, heterodimers of myosins were only detected in low percentage in some systems and it was shown that homodimers are more thermodynamically stable [ 52 ], making it very unlikely that heterodimerization of non-functional dimers could cause a strong dominant negative effect.…”

“…Another explanation could be that myosin tails of other isoforms form heterodimers with XI-K, similar to other systems [ 9 , 52 ]. However, heterodimers of myosins were only detected in low percentage in some systems and it was shown that homodimers are more thermodynamically stable [ 52 ], making it very unlikely that heterodimerization of non-functional dimers could cause a strong dominant negative effect. Consistent with this, we show in this study that overexpression of coiled-coil domains has only a weak effect on P-body movement.…”

Gene transfer, expression, and sarcomeric incorporation of a headless myosin molecule in cardiac myocytes: evidence for a reserve in myofilament motor function

“…Because there was a corresponding decrease in endogenous MHC expression coincident with headless-MHC it is likely that the sarcomere of the transduced cardiac myocyte contained a population of single-headed dimeric MHC motor molecules. Because the headless-MHC construct contained the entire COOH-terminal rod domain, the most important domain for heavy chain assembly into the thick filament (22,29,30), motor domain truncation should not have impaired the ability of headless-MHC to dimerize with endogenous MHC and assemble into the thick filament. In this regard, the observation that headless-MHC expression was greatest 72-96 h after gene delivery while modest contractile deficits were observed at only at 96 h may relate to turnover rate for endogenous MHC (17) delaying actual replacement of endogenous MHC with headless-MHC relative.…”