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A structural model for phosphorylation control of Dictyostelium myosin II thick filament assembly.

Liang W, Warrick HM, Spudich JA - J. Cell Biol. (1999)

Bottom Line: Converting these three threonines to aspartates (3 x Asp myosin II), which mimics the phosphorylated state, inhibits filament assembly in vitro, and 3 x Asp myosin II fails to rescue myosin II- phenotypes.These data, combined with new structural evidence from electron microscopy and sequence analyses, provide evidence that thick filament assembly control involves the folding of myosin II into a bent monomer, which is unable to incorporate into thick filaments.The data are consistent with a structural model for the bent monomer in which two specific regions of the tail interact to form an antiparallel tetrameric coiled-coil structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA.

ABSTRACT
Myosin II thick filament assembly in Dictyostelium is regulated by phosphorylation at three threonines in the tail region of the molecule. Converting these three threonines to aspartates (3 x Asp myosin II), which mimics the phosphorylated state, inhibits filament assembly in vitro, and 3 x Asp myosin II fails to rescue myosin II- phenotypes. Here we report a suppressor screen of Dictyostelium myosin II- cells containing 3 x Asp myosin II, which reveals a 21-kD region in the tail that is critical for the phosphorylation control. These data, combined with new structural evidence from electron microscopy and sequence analyses, provide evidence that thick filament assembly control involves the folding of myosin II into a bent monomer, which is unable to incorporate into thick filaments. The data are consistent with a structural model for the bent monomer in which two specific regions of the tail interact to form an antiparallel tetrameric coiled-coil structure.

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Coiled–coil predictions of Dictyostelium wild-type and 3×Asp myosin IIs. The predictions were generated by the Coils program (Lupas et al. 1991). x-axis, amino acid positions starting from the head–neck junction. y-axis, probability of forming a coiled–coil. A window of 28 amino acids was used to generate the profiles shown.
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Figure 5: Coiled–coil predictions of Dictyostelium wild-type and 3×Asp myosin IIs. The predictions were generated by the Coils program (Lupas et al. 1991). x-axis, amino acid positions starting from the head–neck junction. y-axis, probability of forming a coiled–coil. A window of 28 amino acids was used to generate the profiles shown.

Mentions: The tail domain of Dictyostelium myosin II consists of 1,298 residues, and has no proline interruptions. The coiled–coil prediction algorithm Coils (Lupas et al. 1991) predicts small, distinct regions in the Dictyostelium myosin II tail that have low probabilities to form a coiled–coil structure (Fig. 5). The two most unfavorable regions for coiled–coil structure locate at ∼1,000 and 1,200 Å from the head–neck junction. Consistent with this prediction, to optimize the pattern of charged and uncharged residues for the periodicity of stable coiled–coil structure in the tail, two skips of two amino acids each were necessary to be inserted into the tail sequence lineup at these two regions (Warrick et al. 1986). Similar correlation between the bends observed from EM versus skips in the tail has been shown in smooth and skeletal muscle myosins (Offer 1990), and in Acanthamoeba myosin (Hammer et al. 1987). These results indicate that these two positions at ∼1,000 and 1,200 Å from the head–neck junction are hinge regions in the Dictyostelium tail domain, as seen in other myosin IIs (Tan et al. 1992).


A structural model for phosphorylation control of Dictyostelium myosin II thick filament assembly.

Liang W, Warrick HM, Spudich JA - J. Cell Biol. (1999)

Coiled–coil predictions of Dictyostelium wild-type and 3×Asp myosin IIs. The predictions were generated by the Coils program (Lupas et al. 1991). x-axis, amino acid positions starting from the head–neck junction. y-axis, probability of forming a coiled–coil. A window of 28 amino acids was used to generate the profiles shown.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2169343&req=5

Figure 5: Coiled–coil predictions of Dictyostelium wild-type and 3×Asp myosin IIs. The predictions were generated by the Coils program (Lupas et al. 1991). x-axis, amino acid positions starting from the head–neck junction. y-axis, probability of forming a coiled–coil. A window of 28 amino acids was used to generate the profiles shown.
Mentions: The tail domain of Dictyostelium myosin II consists of 1,298 residues, and has no proline interruptions. The coiled–coil prediction algorithm Coils (Lupas et al. 1991) predicts small, distinct regions in the Dictyostelium myosin II tail that have low probabilities to form a coiled–coil structure (Fig. 5). The two most unfavorable regions for coiled–coil structure locate at ∼1,000 and 1,200 Å from the head–neck junction. Consistent with this prediction, to optimize the pattern of charged and uncharged residues for the periodicity of stable coiled–coil structure in the tail, two skips of two amino acids each were necessary to be inserted into the tail sequence lineup at these two regions (Warrick et al. 1986). Similar correlation between the bends observed from EM versus skips in the tail has been shown in smooth and skeletal muscle myosins (Offer 1990), and in Acanthamoeba myosin (Hammer et al. 1987). These results indicate that these two positions at ∼1,000 and 1,200 Å from the head–neck junction are hinge regions in the Dictyostelium tail domain, as seen in other myosin IIs (Tan et al. 1992).

Bottom Line: Converting these three threonines to aspartates (3 x Asp myosin II), which mimics the phosphorylated state, inhibits filament assembly in vitro, and 3 x Asp myosin II fails to rescue myosin II- phenotypes.These data, combined with new structural evidence from electron microscopy and sequence analyses, provide evidence that thick filament assembly control involves the folding of myosin II into a bent monomer, which is unable to incorporate into thick filaments.The data are consistent with a structural model for the bent monomer in which two specific regions of the tail interact to form an antiparallel tetrameric coiled-coil structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA.

ABSTRACT
Myosin II thick filament assembly in Dictyostelium is regulated by phosphorylation at three threonines in the tail region of the molecule. Converting these three threonines to aspartates (3 x Asp myosin II), which mimics the phosphorylated state, inhibits filament assembly in vitro, and 3 x Asp myosin II fails to rescue myosin II- phenotypes. Here we report a suppressor screen of Dictyostelium myosin II- cells containing 3 x Asp myosin II, which reveals a 21-kD region in the tail that is critical for the phosphorylation control. These data, combined with new structural evidence from electron microscopy and sequence analyses, provide evidence that thick filament assembly control involves the folding of myosin II into a bent monomer, which is unable to incorporate into thick filaments. The data are consistent with a structural model for the bent monomer in which two specific regions of the tail interact to form an antiparallel tetrameric coiled-coil structure.

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