Further characterization of light and heavy sarcoplasmic reticulum vesicles. Identification of the ‘sarcoplasmic reticulum feet’ associated with heavy sarcoplasmic reticulum vesicles

Campbell, Kevin P.; Franzini‐Armstrong, Clara; Shamoo, Adil E.

doi:10.1016/0005-2736(80)90293-x

Cited by 180 publications

(92 citation statements)

References 33 publications

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“…1 is concentrated in junctional sarcoplasmic reticulum (SR) terminal cisternae as part of the multimeric Ca 2ϩ -release channel complex (1)(2)(3)(4)(5)(6)(7)(8) that includes the cardiac ryanodine receptor (9,10), junctin (11), and cardiac triadin-1 (12). The cardiac isoform of CSQ (13,14) exhibits 65% sequence identity to the fast-twitch form (15), but its carboxyl terminus extends an additional 24 residues and contains CK2 phosphorylation sites (16).…”

Section: Cardiac Calsequestrin (Csq)mentioning

confidence: 99%

Mass Spectrometry of Cardiac Calsequestrin Characterizes Microheterogeneity Unique to Heart and Indicative of Complex Intracellular Transit

O’Brian

Ram

Kiarash

et al. 2002

Journal of Biological Chemistry

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Cardiac calsequestrin concentrates in junctional sarcoplasmic reticulum in heart and skeletal muscle cells by an undefined mechanism. During transit through the secretory pathway, it undergoes an as yet uncharacterized glycosylation and acquires phosphate on CK2-sensitive sites. In this study, we have shown that active calsequestrin phosphorylation occurred in nonmuscle cells as well as muscle cells, reflecting a widespread cellular process. To characterize this post-translational modification and resolve individual molecular mass species, we subjected purified calsequestrin to mass spectrometry using electrospray ionization. Mass spectra showed that calsequestrin glycan structure in nonmuscle cells was that expected for an endoplasmic reticulum-localized glycoprotein and showed that each glycoform existed as four mass peaks representing molecules that also had 0 -3 phosphorylation sites occupied. In heart, mass peaks indicated carbohydrate modifications characteristic of transit through Golgi compartments. Phosphorylation did not occur on every glycoform present, suggesting a far more complex movement of calsequestrin molecules in heart cells. Significant amounts of calsequestrin contained glycan with only a single mannose residue, indicative of a novel post-endoplasmic reticulum mannosidase activity. In conclusion, glyco-and phosphoforms of calsequestrin chart a complex cellular transport in heart, with calsequestrin following trafficking pathways not present or not accessible to the same molecules in nonmuscle.

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Section: Cardiac Calsequestrin (Csq)mentioning

confidence: 99%

Mass Spectrometry of Cardiac Calsequestrin Characterizes Microheterogeneity Unique to Heart and Indicative of Complex Intracellular Transit

O’Brian

Ram

Kiarash

et al. 2002

Journal of Biological Chemistry

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“…FIBER, A-, AND I-BAND COMPOSITION : The results of analysis using large probe diameters (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) [.m) averaging over several sarcomeres of control and tetanized fibers are shown in Table I. The elemental concentrations are expressed on a dry weight basis.…”

Section: Electron-probe Analysismentioning

confidence: 99%

“…The combined results of the analysis ofthe TC and of the LSR are also inconsistent with the interpretation of Ca" flux data that ascribe a relatively small (0.2 mmol/kg wet muscle), fast exchanging (time constant = 2.7 min) component as representing the Ca content of the TC, and a larger (0.54 mmole/kg wet muscle) slowly exchanging (time-constant = 1,244 min) component to the LSR (54). The relatively low Ca content of the LSR that, in contrast to the TIC, contains little or no calsequestrin (12,51,52,66), does support the conclusion that the free Ca" in the SR is in the low millimolar range (104).…”

Section: The Composition Of the Cytoplasm And Of The Lsr During Tetanmentioning

confidence: 99%

Calcium release and ionic changes in the sarcoplasmic reticulum of tetanized muscle: an electron-probe study.

Somlyo¹,

González‐Serratos²,

Shuman³

et al. 1981

The Journal of Cell Biology

421

223

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Approximately 60-70% of the total fiber calcium was localized in the terminal cisternae (TC) in resting frog muscle as determined by electron-probe analysis of ultrathin cryosections . During a 1 .2 s tetanus, 59% (69 mmol/kg dry TC) of the calcium content of the TC was released, enough to raise total cytoplasmic calcium concentration by -1 mM . This is equivalent to the concentration of binding sites on the calcium-binding proteins (troponin and parvalbumin) in frog muscle . Calcium release was associated with a significant uptake of magnesium and potassium into the TC, but the amount of calcium released exceeded the total measured cation accumulation by 62 mEq/kg dry weight . It is suggested that most of the charge deficit is apparent, and charge compensation is achieved by movement of protons into the sarcoplasmic reticulum (SR) and/or by the movement of organic co-or counterions not measured by energy dispersive electron-probe analysis . There was no significant change in the sodium or chlorine content of the TIC during tetanus. The unchanged distribution of a permeant anion, chloride, argues against the existence of a large and sustained transSR potential during tetanus, if the chloride permeability of the in situ SR is as high as suggested by measurements on fractionated SR .The calcium content of the longitudinal SR (LSR) during tetanus did not show the LSR to be a major site of calcium storage and delayed return to the TC . The potassium concentration in the LSR was not significantly different from the adjacent cytoplasmic concentration. Analysis of small areas of I-band and large areas, including several sarcomeres, suggested that chloride is anisotropically distributed, with some of it probably bound to myosin . In contrast, the distribution of potassium in the fiber cytoplasm followed the water distribution . The mitochondrial concentration of calcium was low and did not change significantly during a tetanus. The TIC of both tetanized and resting freeze-substituted muscles contained electron-lucent circular areas . The appearance of the TIC showed no evidence of major volume changes during tetanus, in agreement with the estimates of unchanged (-72%) water content of the TIC obtained with electron-probe analysis .The release of Ca from and its subsequent return to the triadic portion of the sarcoplasmic reticulum (SR) (28,80,82) are the major determinants of the contractile cycle of striated muscle (for review, see reference 24) . Since the demonstration of the SR as the ATP-dependent relaxing factor (57), a wealth of information has been accumulated about the kinetics and THE JOURNAL OF CELL BIOLOGY " VOLUME 90 SEPTEMBER 1981 577-594 © The Rockefeller University Press -0021-9525/81/09/0577/18 $1 .00 mechanisms of calcium uptake by the SR (e.g., 41,48,63,104,106, and for review, see references 62, 102). In contrast, comparatively little is known about the mechanism of release and associated ion movements, largely because isolated SR preparations do not lend themselves to reproduction of the ph...

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“…The total concentration of Ca 2ϩ in the SR is as high as 50 mM (2), but a large portion of this Ca 2ϩ is bound to a specific protein, calsequestrin.…”

mentioning

confidence: 99%

Polymerization of Calsequestrin

Park

Dunker

et al. 2003

Journal of Biological Chemistry

114

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Further characterization of light and heavy sarcoplasmic reticulum vesicles. Identification of the ‘sarcoplasmic reticulum feet’ associated with heavy sarcoplasmic reticulum vesicles

Cited by 180 publications

References 33 publications

Mass Spectrometry of Cardiac Calsequestrin Characterizes Microheterogeneity Unique to Heart and Indicative of Complex Intracellular Transit

Mass Spectrometry of Cardiac Calsequestrin Characterizes Microheterogeneity Unique to Heart and Indicative of Complex Intracellular Transit

Calcium release and ionic changes in the sarcoplasmic reticulum of tetanized muscle: an electron-probe study.

Polymerization of Calsequestrin

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