High Resolution Cryo-EM Structure of <i>Drosophila</i> Thick Filaments

Yeganeh, Fatemeh Abbasi; Rastegarpouyani, Hosna; Taylor, Kenneth A.

doi:10.1017/s1431927622004664

Cited by 4 publications

(4 citation statements)

References 5 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We observe four non-myosin densities in the three species of insect studied at a subnanometer resolution: stretchin-klp, paramyosin, flightin, and myofilin. We observed stretchin-klp only in Drosophila and only on the surface of the thick filament [13,14]. The thick filament surfaces of Bombus and Lethocerus were free of surface proteins.…”

Section: Nonmyosin Densitiesmentioning

confidence: 70%

“…All invertebrate thick filaments appear to contain paramyosin, though the amounts appear to be quite variable [24]. Two other proteins, flightin and myofilin, have been found in Lethocerus and Drosophila thick filaments and a third, stretchin-klp, has been identified in reconstructions of Drosophila [13,14] but is not seen in Lethocerus. Other proteins such as projectin, kettin, and obscurin are present within flight muscle thick filaments, but their quantities are either too low relative to myosin to show up in a helically averaged 3-D image reconstruction, or they are located in the bare zone, or the filament ends which are areas that are avoided when selecting segments for reconstruction.…”

Section: Non-myosin Densitiesmentioning

confidence: 99%

“…The relaxed thick filament reconstructions from Drosophila melanogaster failed to show any ordered myosin heads [13,14] leaving open the question of whether this particular muscle forms an IHM that is itself disordered, because it fails to attach to the filament backbone, or whether the motif forms at all. Supporting the former was the presence of non-myosin proteins decorating the filament backbone in such a way that they could provide a steric block to the binding of myosin heads.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution

Rahmani

Yeganeh

et al. 2022

IJMS

Self Cite

View full text Add to dashboard Cite

Four insect orders have flight muscles that are both asynchronous and indirect; they are asynchronous in that the wingbeat frequency is decoupled from the frequency of nervous stimulation and indirect in that the muscles attach to the thoracic exoskeleton instead of directly to the wing. Flight muscle thick filaments from two orders, Hemiptera and Diptera, have been imaged at a subnanometer resolution, both of which revealed a myosin tail arrangement referred to as “curved molecular crystalline layers”. Here, we report a thick filament structure from the indirect flight muscles of a third insect order, Hymenoptera, the Asian bumble bee Bombus ignitus. The myosin tails are in general agreement with previous determinations from Lethocerus indicus and Drosophila melanogaster. The Skip 2 region has the same unusual structure as found in Lethocerus indicus thick filaments, an α-helix discontinuity is also seen at Skip 4, but the orientation of the Skip 1 region on the surface of the backbone is less angled with respect to the filament axis than in the other two species. The heads are disordered as in Drosophila, but we observe no non-myosin proteins on the backbone surface that might prohibit the ordering of myosin heads onto the thick filament backbone. There are strong structural similarities among the three species in their non-myosin proteins within the backbone that suggest how one previously unassigned density in Lethocerus might be assigned. Overall, the structure conforms to the previously observed pattern of high similarity in the myosin tail arrangement, but differences in the non-myosin proteins.

show abstract

Section: Nonmyosin Densitiesmentioning

confidence: 70%

Section: Non-myosin Densitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution

Rahmani

Yeganeh

et al. 2022

IJMS

Self Cite

View full text Add to dashboard Cite

show abstract

“…A mutant Drosophila flight muscle that could not be phosphorylated on the RLC also failed to show ordered heads. Drosophila flight muscle also expresses a non-myosin protein, stretchin-klp, which was previously found on the thick filament backbone surface [31,69] in a position to obstruct binding of the free myosin head to the filament surface thereby preventing the ordering of the IHM. Whether or not stretchin-klp prevents IHM formation is a separate question.…”

Section: Disordered Myosin Headsmentioning

confidence: 97%

Structure of the Drosophila melanogaster Flight Muscle Myosin Filament at 4.7 Å Resolution Reveals New Details of Non-Myosin Proteins

Abbasi Yeganeh,

Rastegarpouyani,

et al. 2023

IJMS

Self Cite

View full text Add to dashboard Cite

Striated muscle thick filaments are composed of myosin II and several non-myosin proteins which define the filament length and modify its function. Myosin II has a globular N-terminal motor domain comprising its catalytic and actin-binding activities and a long α-helical, coiled tail that forms the dense filament backbone. Myosin alone polymerizes into filaments of irregular length, but striated muscle thick filaments have defined lengths that, with thin filaments, define the sarcomere structure. The motor domain structure and function are well understood, but the myosin filament backbone is not. Here we report on the structure of the flight muscle thick filaments from Drosophila melanogaster at 4.7 Å resolution, which eliminates previous ambiguities in non-myosin densities. The full proximal S2 region is resolved, as are the connecting densities between the Ig domains of stretchin-klp. The proteins, flightin, and myofilin are resolved in sufficient detail to build an atomic model based on an AlphaFold prediction. Our results suggest a method by which flightin and myofilin cooperate to define the structure of the thick filament and explains a key myosin mutation that affects flightin incorporation. Drosophila is a genetic model organism for which our results can define strategies for functional testing.

show abstract

Structure and Arrangement of Non-myosin Proteins in the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus by CryoEM

Rahmani

Yeganeh

et al. 2023

Microscopy and Microanalysis

View full text Add to dashboard Cite

High Resolution Cryo-EM Structure of Drosophila Thick Filaments

Cited by 4 publications

References 5 publications

Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution

Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution

Structure of the Drosophila melanogaster Flight Muscle Myosin Filament at 4.7 Å Resolution Reveals New Details of Non-Myosin Proteins

Structure and Arrangement of Non-myosin Proteins in the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus by CryoEM

Contact Info

Product

Resources

About