Abnormal properties of Mg2+-ATPase in transverse tubule membranes from dystrophic chicken

Megías, Alicia; Saborido, Ana

doi:10.1016/0003-9861(90)90238-t

Cited by 6 publications

(6 citation statements)

References 32 publications

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“…Dystrophic muscle microsomes showed lower Ca2~-ATPase(a SR marker) activity and higher Mg2~-ATPaseand ouabain-sensitive Na + K + -ATPase activities [two proteins located at the surface membrane (SM)] and cholesterol content than NMV. This could indicate that, in agreement with MegIas and Saborido (1990), the SM proportion is higher in DMV. However, it could also reflect the increased content of sarcolemmal enzyme markers in dystrophic muscle, as assessed by the elevation of ouabain-binding sites in the pathological tissue (AbdelAziz et al, 1985;Dunn et al, 1995).…”

Section: Characterization Of Microsomal Membranes From Normal and Dyssupporting

confidence: 58%

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle

Cabezas-Herrera

Moral‐Naranjo

Campoy

et al. 1997

Journal of Neurochemistry

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Abstract:The distribution and glycosylation of acetyicholinesterase (AChE) forms in vesicles derived from sarcoplasmic reticulum of normal muscle (NMV) were investigated and compared with those from dystrophic muscle vesicles (DMV). AChE activity was similar in NMV and DMV. Most of the AChE in NMV and half in DMV were released with Triton X-1 00. Asymmetric (A 12) and globular hydrophilic and amphiphilic (G~, G~, G~, and G~) AChE species occurred in NMV and DMV, the lighter forms being predominant. The percentage of G~and G~de-creased in DMV. A fraction of the AChE that could not be extracted with detergent was detached with collagenase. Most of the detergent-released A12 AChE from NMV and nearly half in DMV failed to bind to Ricinus communis agglutinin (RCA-I). Conversely, the collagenase-detached isoforms bound to RCA, revealing that asymmetric AChE associated with internal membranes or basal lamina differed in glycosylation. Moreover, nearly half of GÃChE in DMV and a few in NMV bound to RCA. Most of the RCA-unreactive Gforms in NMV come from sarcolemma. The results indicate that dystrophy induces minor changes in the distribution and glycosylation of AChE forms in internal membranes of muscle.

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Section: Characterization Of Microsomal Membranes From Normal and Dyssupporting

confidence: 58%

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle

Cabezas-Herrera

Moral‐Naranjo

Campoy

et al. 1997

Journal of Neurochemistry

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“…In either the absence or the presence of activators, the ecto-ATPase activity continued to increase over all concentrations of ATP tested (5 µM to 10 mM) ( Figure 6A). In agreement with previous studies [5,7,9], the ecto-ATPase by itself exhibited biphasic double-reciprocal plots, consistent with negative co-operativity or interconvertible substrate-binding sites that do not coexist independently ; in the presence of Con A this behaviour was eliminated, producing simple Michaelis-Menten kinetics ( Figure 6B) with both increased K m and increased V max . Although digitonin (0.5 mg\ml) enhanced ecto-ATPase activity at all ATP concentrations used, the biphasic response was not abolished and apparent K m values for the high-affinity and lowaffinity ATP-binding sites did not change significantly.…”

Section: Activatorsupporting

confidence: 92%

“…One of the most interesting features is the response to concanavalin A (Con A) and other lectins. Con A stimulates the activity of the membranebound enzyme 6-10-fold, abolishes the negative co-operativity of ATP, yielding classical Michaelis-Menten kinetics, changes the unusual temperature dependence curve of activity to a linear relationship up to 45 mC, and eliminates inhibition by Triton X-100 and saponin [5][6][7]9]. Moulton et al [5] proposed that these effects occur through the modulation by Con A of a low-affinity nucleotide regulatory site where ATP and Triton X-100, as well as a variety of lipophilic and amphipathic agents [10], could interact.…”

Section: Introductionmentioning

confidence: 99%

Regulation of transverse tubule ecto-ATPase activity in chicken skeletal muscle

Megías

Martinez-Senac

Delgado

et al. 2001

Biochemical Journal

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Transverse tubule (T-tubule) ecto-ATPase from chicken skeletal muscle is an integral membrane glycoprotein that seems to exist as a homodimer and exhibits unusual properties. Treatment of T-tubule membranes with concanavalin A (Con A) did not significantly affect the thermal variation of the fluorescence anisotropy of vesicles labelled with 1,6-diphenyl-1,3,5-hexatriene or trimethylammonium-1,6-diphenyl-1,3,5-hexatriene. Cross-linking of membrane components with glutaraldehyde elicited effects on ecto-ATPase activity very similar to those of Con A treatment: a severalfold increase in activity, a decrease in Triton X-100 sensitivity and a requirement to be present before ATP to exert its action. In addition, glutaraldehyde and Con A normalized the temperature dependence and the kinetic behaviour of the enzyme. Membrane-perturbing agents (detergents, alcohols and cholesterol oxidase), with the sole exception of digitonin, caused a marked decrease in ecto-ATPase activity; the prior presence of Con A prevented this inhibition, whereas when the lectin was added after the membrane perturbing agent, recovery of the activity was not always possible. The addition of nucleotides before Con A led to a suppression of ecto-ATPase stimulation; it occurred when the nucleotide was hydrolysed (ATP or UTP) and when it was not (adenosine 5′-[β,γ-imido]triphosphate) and even in the presence of 3mM Pi. A model is proposed for the complex regulatory mechanisms of chicken T-tubule ecto-ATPase that involves the occurrence of two different catalytic states in an equilibrium modulated by lectins and cross-linking agents, by the structure of the membrane and by the presence of ligands for a regulatory site.

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“…Several laboratories have reported structural and molecular abnormalities in the affected muscles of dystrophic chicken: disarrangement of fibre structure with degeneration of contractile apparatus and alterations in the expression of myofibrillar protein isoforms; marked proliferation of T-tubular and junctional SR membranes accompanied by structural and biochemical defects, such as changes in the spatial relationship between T-tubules and SR, an over-expression of ryanodine receptor sites or a decrease in Mg2+-ATPase activity (Scales & Yasumura, 1982;Martonosi, 1989;Megias & Saborido, 1990;Pessah & Schiedt, 1990;Hayakawa et al, 1993). Since dystrophic chicken muscle present a normal expression of dystrophin (Hoffman et al, 1988), the lacking protein in DMD muscle, the primary cause of the avian disorder must be different from that of DMD.…”

Section: Introductionmentioning

confidence: 99%

“…Since dystrophic chicken muscle present a normal expression of dystrophin (Hoffman et al, 1988), the lacking protein in DMD muscle, the primary cause of the avian disorder must be different from that of DMD. The striking proliferation and alterations of T-tubules observed in dystrophic chicken muscle (Malouf et al, 1981;Scales & Yasumura, 1982;Martonosi, 1989;Megias & Saborido, 1990), together with the increased total calcium content in pectoral muscles and the reported retardation of dystrophic symptoms in chickens treated with calcium channel blockers (Hudecki et al, 1984), prompted us to investigate the possible involvement of voltage-dependent calcium channels in chicken dystrophy pathological processes.…”

Section: Introductionmentioning

confidence: 99%

Dihydropyridine receptors in transverse tubules from normal and dystrophic chicken skeletal muscle

Moro

Saborido

Delgado

et al. 1995

J Muscle Res Cell Motil

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Calcium overload is a fundamental pathogenic event associated with chronic muscle degeneration in muscular dystrophies. The possibility that L-type voltage-dependent calcium channels were involved in the etiology of chicken muscular dystrophy was investigated by studying the dihydropyridine receptors in transverse tubule membranes isolated from skeletal muscle of normal (line 412) and dystrophic (line 413) chickens. The yield of T-tubular protein from dystrophic muscle was considerably increased compared with that from normal muscle (2.51 +/- 0.18 vs 1.04 +/- 0.31 mg protein x 100 g muscle-1). The binding of the calcium channel antagonist (+) [3H]PN200-110 to the dihydropyridine receptor in transverse tubule preparations was relatively slow, markedly affected by temperature and required divalent cations. (+) [3H]PN200-110 equilibrium binding assays revealed a single class of high-affinity sites and showed that maximum binding capacity (Bmax) (3.17 +/- 0.47 for normal and 3.51 +/- 0.52 pmol x mg protein-1 for dystrophic transverse tubules) and dissociation constant (Kd) (0.32 +/- 0.07 and 0.26 +/- 0.09 nM, respectively) were not significantly different in normal and dystrophic membranes. Kinetic studies indicated that normal and dystrophic transverse tubules did not differ significantly in association (2.54 x 10(6) and 2.27 x 10(6) M(-1)s(-1), respectively) and dissociation (8.5 x 10(-4) and 9.3 x 10(-4)s(-1), respectively) rate constants. Since dissociation kinetics for both preparations were monoexponential under all the experimental conditions employed, no low-affinity binding sites for (+) [3H]PN200-110 could be detected in chicken transverse tubules membranes. However, immunoblot assay, using a monoclonal antibody, revealed that dystrophic transverse tubules as compared with normal membranes were enriched twofold with the alpha 1-subunit of the dihydropyridine receptor. Therefore, although dihydropyridine-binding sites were not altered in transverse tubule membranes from dystrophic chicken skeletal muscle, both the increased yield in T-tubule vesicles and the enhanced immunodetection of the alpha 1-subunit of the dihydropyridine receptor, suggest that total content in dihydropyridine receptor is higher in dystrophic than in normal muscle.

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Abnormal properties of Mg2+-ATPase in transverse tubule membranes from dystrophic chicken

Cited by 6 publications

References 32 publications

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle

Regulation of transverse tubule ecto-ATPase activity in chicken skeletal muscle

Dihydropyridine receptors in transverse tubules from normal and dystrophic chicken skeletal muscle

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Abnormal properties of Mg2+-ATPase in transverse tubule membranes from dystrophic chicken

Cited by 6 publications

References 32 publications

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2dy Mouse Muscle

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2dy Mouse Muscle

Regulation of transverse tubule ecto-ATPase activity in chicken skeletal muscle

Dihydropyridine receptors in transverse tubules from normal and dystrophic chicken skeletal muscle

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Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2^dy Mouse Muscle