New proline-rich proteins in isolated insect Z-discs

Sainsbury, G M; Bullard, Belinda

doi:10.1042/bj1910333

Cited by 27 publications

(13 citation statements)

References 26 publications

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“…proteins have been identified (Saide & Ullrick, 1974;Bullard & Sainsbury, 1977;Hammond & Goll, 1975;Sainsbury & Bullard, 1980); their mode of assembly has not been determined. Moreoever, it is not known what factors dictate the Z-band structure found in a given tissue.…”

Section: Introductionmentioning

confidence: 97%

Z-band proteins in the flight muscle and leg muscle of the honeybee

Saide

Chin-Bow

Hogan-Sheldon

et al. 1990

J Muscle Res Cell Motil

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Monoclonal antibodies (mAb's) have been raised against proteins in preparations of Z-discs isolated from honeybee fibrillar flight muscle. These antibodies have identified four Z-disc antigens on immunoblots of honeybee fibrillar proteins. Antibody alpha binds to the 90-100 kD protein, alpha-actinin; mAb P interacts with the protein, projectin, an extremely large polypeptide (greater than 600kD) found in the connecting filaments which link thick filaments to the Z-band in insect asynchronous flight muscle. Two other mAb's recognize previously uncharacterized insect Z-band proteins. Monoclonal antibody Z(400) binds to a pair of proteins with molecular masses near 400 kD and 600 kD. Antibody Z(175) recognizes two components, 158 kD and 175 kD, that are not only immunologically similar but have nearly identical peptide maps. Indirect immunofluorescence microscopy studies show that the proteins recognized by mAb's alpha, Z(175) and Z(400) are located at the Z-band, while the mAb P antigen is found on either side of it. Three of the four antibodies we have obtained recognize leg muscle proteins. Monoclonal antibodies alpha and P comigrate on SDS gels with analogous components from flight muscle. Only the smaller of the two proteins identified in flight muscle by mAb Z(400) is found in leg muscle, however. Furthermore, no Z(175) antigens have been detected in the non-fibrillar tissue by either monoclonal or polyclonal antibodies. Immunofluorescence microscopy studies localize the alpha and Z(400) antigens at the Z-line in leg muscle fibrils. Surprisingly, however, mAb P binds within the A-bands of synchronous fibres, not between the A- and Z-bands as in asynchronous fibrillar muscle.

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Section: Introductionmentioning

confidence: 97%

Z-band proteins in the flight muscle and leg muscle of the honeybee

Saide

Chin-Bow

Hogan-Sheldon

et al. 1990

J Muscle Res Cell Motil

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“…We have previously isolated Z-discs from insect flight muscle that are relatively free from other myofibrillar components and retain the native lattice structure (Sainsbury & Hulmes, 1977;Sainsbury & Bullard, 1980). The preparation contains a high proportion of two hydrophobic, proline-rich proteins (zeelins 1 and 2) though it is not known yet how these proteins are associated with the Z-disc.…”

Section: Introductionmentioning

confidence: 98%

Digestion of proteins associated with the Z-disc by calpain

Bullard¹,

Sainsbury²,

Miller³

1990

J Muscle Res Cell Motil

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The Z-disc of striated muscle is degraded by the Ca2(+)-activated proteinase, calpain, during autolysis of muscle fibres. The effect of calpain on proteins in preparations of Z-discs isolated from Lethocerus flight muscle has been studied. Calpain releases alpha-actinin from the Z-disc and digests two hydrophobic proteins associated with the Z-disc, zeelin 1 (35 kD) and zeelin 2 (23 kD). The Ca2+ sensitivity of zeelin digestion is shifted to lower Ca2+ concentrations (within the physiological range) in the presence of the phospholipids phosphatidyl inositol or phosphatidyl choline and diacylglycerol. The release of alpha-actinin is not affected by phospholipid. Preparations of isolated Z-discs have five times as much associated phospholipid (w/w) as myofibrils and the composition of the lipid differs from that of myofibrils. In muscle fibres the action of calpain on zeelins may be controlled by the composition of phospholipid in the fibres as well as by Ca2+.

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“…Furthermore, Bullard et al (1977) have demonstrated an extra protein which lies between the Z line and the A filaments, by staining with antibody, and Sainsbury & Bullard (1980) tentatively attribute the 180 kDalton and possibly the 105 kDalton proteins which they extract from Z disks to this connecting material.…”

Section: Structural Studiesmentioning

confidence: 99%

The elasticity of relaxed insect fibrillar flight muscle.

White¹

1983

The Journal of Physiology

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SUMMARY1. The mechanical properties of glycerol-extracted fibres from the dorsal longitudinal muscle of Lethocerus have been determined by sinusoidal and transient analysis in the time range 1 ms-1000 s, and from rest length to 10% strain for fibres in relaxing and rigor solutions. The fibres behave reversibly up to strains of about 5 %, but reach an elastic limit in the range 5-9 % strain, depending upon the rate of strain.2. Electron micrographs of fibres at different degrees of stretch, and after partial extraction of the contractile proteins, suggest that a connexion between the end of the A filament and the Z line, named a C filament, is responsible for the high stiffness of the relaxed muscle.3. Estimates are made of the compliance of the A, I and C filaments. The mechanical response of the relaxed muscle, over the entire frequency range studied, is assignable to the C filaments.4. An analysis of the stiffness of the fibres at different tensions in activating and relaxing solutions, and in fibres relaxed by orthovanadate, shows that the C filaments still exert their mechanical effect in the active muscle. That is, the response of the active muscle consists of the contribution from the cross-bridges plus that of the C filaments, acting mechanically in parallel. This situation is incompatible with earlier explanations ofthe fully activated mechanical dynamics offibrillar muscle. Alternative explanations at the cross-bridge level are described in the paper that follows this one.

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New proline-rich proteins in isolated insect Z-discs

Cited by 27 publications

References 26 publications

Z-band proteins in the flight muscle and leg muscle of the honeybee

Z-band proteins in the flight muscle and leg muscle of the honeybee

Digestion of proteins associated with the Z-disc by calpain

The elasticity of relaxed insect fibrillar flight muscle.

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