The cortical actin-membrane cytoskeleton of unfertilized sea urchin eggs: Analysis of the spatial organization and relationship of filamentous actin, nonfilamentous actin, and egg spectrin

Bonder, Edward M.; Fishkind, Douglas J.; Cotran, Nina M.; Begg, David A.

doi:10.1016/0012-1606(89)90105-x

Cited by 63 publications

(45 citation statements)

References 63 publications

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“…For example, both mouse blastomeres [Sobel et al, 19881 and postimplant mouse embryos [Damjanov et al, 19861 demonstrate granular, cytoplasmic a-spectrin immunolocalization. Similar localizations of spectrin to discrete intracellular vesicular structures has been reported for sea urchin eggs [Bonder et al, 1989;., 19881, lymphocytes [Black et al, 19881, and regenerating axons [Koenig et al, 19851. Interestingly, in the case of lymphocytes [Black et al, 19881, and perhaps sea urchin [Bonder et al, 1989;., 19881, vesicular localizations are often found closely opposed to the Golgi and may be indicative of spectrin preassembled ized consist of a common a-subunit (240 kD) paired with a tissue-specific P-subunit from either erythrocyte (220 or 230 kD), brain (235 kD), or intestinal brush border (260 kD).…”

Section: Diverse Nonerythroid Spectrin Lmmunolocalizationsupporting

confidence: 69%

“…role of the spectrins is that of regulating receptorfilament interactions. As such, it is conceivable that the spectrins may be involved with such processes as membrane trafficking in the intestinal brush border and sea urchin egg/embryo [Hirokawa et al, 1982[Hirokawa et al, , 1983Pearl et al, 1984;Bonder et al, 1989;Fishkind et al, 19881, secretion in chromaffin cells [Perrin and Aunis, 19851, topographic membrane assembly in epithelial cells Veshnock, 1986, 1987b;Morrow et al, 19891, receptor regulation and presentation in the nervous system [Lynch and Baudry, 19841, lymphocyte capping [reviewed in Bourguignon and Bourguignon, 19841, or substrate-mediated endothelial cell differentiation [Pratt et al, 19841 (Fig. 4).…”

Section: General Considerationsmentioning

confidence: 99%

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Functional diversity among spectrin isoforms

Coleman

Fishkind

Mooseker

et al. 1989

Cell Motil. Cytoskeleton

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115

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The purpose of this review on spectrin is to examine the functional properties of this ubiquitous family of membrane skeletal proteins. Major topics include spectrin-membrane linkages, spectrin-filament linkages, the subcellular localization of spectrins in various cell types and a discussion of major functional differences between erythroid and nonerythroid spectrins. This includes a summary of studies from our own laboratories on the functional and structural comparison of avian spectrin isoforms which are comprised of a common alpha subunit and a tissue-specific beta subunit. Consequently, the observed differences among these spectrins can be assigned to differences in the properties of the beta subunits.

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Section: Diverse Nonerythroid Spectrin Lmmunolocalizationsupporting

confidence: 69%

Section: General Considerationsmentioning

confidence: 99%

Functional diversity among spectrin isoforms

Coleman

Fishkind

Mooseker

et al. 1989

Cell Motil. Cytoskeleton

Self Cite

115

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“…In addition, a concentration of nonfilamentous actin would greatly increase the rate of assembly upon activation, by removing the dependence on the diffusion of actin subunits. In the case of sea urchin eggs, where similar structures of nonfilamentous actin have been detected in the cortex, the concentration of actin may be especially important given the large diameter of the cell and the rapid response of actin assembly following fertilization-induced activation of second messengers near the membrane (Burgess and Schroeder, 1977;Spudich et al, 1988;Bonder et al, 1989). Without the concentration of actin, one would expect the assembly of actin filaments to be severely limited by diffusion.…”

Section: Discussionmentioning

confidence: 99%

“…First, in Thyone sperm, unpolymerized actin is known to be concentrated at the "acrosomal cup; and undergoes rapid assembly into filaments during elongation of the acrosomal process following sperm activation (Tilney, 1976a(Tilney, ,b, 1978. Second, in unfertilized sea urchin eggs, nonfilamentous actin is found to concentrate in the cortex and is thought to assemble rapidly into cortical filaments following fertilization (Spudich et al, 1988;Bonder et al, 1989). These observations raise the interesting possibility that other cell types may use a similar strategy of localizing a storage form of nonfilamentous actin in regions of high assembly activities.…”

mentioning

confidence: 99%

Localization and dynamics of nonfilamentous actin in cultured cells [published erratum appears in J Cell Biol 1993 Nov;123(3):following 767]

Cao¹

1993

The Journal of Cell Biology

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Abstract. Although the distribution of filamentous actin is well characterized in many cell types, the distribution of nonfilamentous actin remains poorly understood. To determine the relative distribution of filamentous and nonfilamentous actin in cultured NRK cells, we have used a number of labeling agents that differ with respect to their specificities toward the filamentous or nonfilamentous form, including monoclonal and polyclonal anti-actin antibodies, vitamin D-binding protein (DBP), and fluorescent phalloidin. Numerous punctate structures were identified that bind poorly to phalloidin but stain positively with several anti-actin antibodies. These bead structures also stain with DBP, suggesting that they are enriched in nonfilamentous actin. Similar punctate structures were observed after the microinjection of fluorescently labeled actin into living cells, allowing us to examine their dynamics in living cells. The actin-containing punctate structures were observed predominantly in the region behind lamellipodia, particularly in spreading cells induced by wounding confluent monolayers. Time-lapse recording of cells injected with fluorescent actin indicated that they form continuously near the leading edge and move centripetally toward the nucleus. Our results suggest that at least part of the unpolymerized actin molecules are localized at discrete sites, possibly as complexes with monomer sequestering proteins. These structures may represent transient storage sites of G-actin within the cell which can be transformed rapidly into actin filaments upon stimulation by specific signals.

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“…We herein displayed a-spectrin degradation during parthenogenetic egg activation using a calpain-specific a-spectrin-breakdown products antibody. a-Spectrin has been detected previously in the cortical area of mouse eggs (Bonder et al 1989, Bonder & Fishkind 1995 and adjacent to the meiotic spindle (Schatten et al 1986). Correspondingly, both calpain isoforms appeared to be localized to the same area.…”

Section: Ionomycinmentioning

confidence: 86%

Expression and possible involvement of calpain isoforms in mammalian egg activation

Ben‐Aharon

Haim²,

Shalgi³

et al. 2005

Reproduction

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At fertilization in mammals, the spermatozoon triggers a unique signal transduction mechanism within the egg, leading to its activation. It is well accepted that the earliest event observed in all activated eggs is an abrupt rise in intracellular calcium concentrations. However, little is known regarding the downstream proteins that are activated by this rise in calcium. Calpains constitute a family of intracellular calcium-dependent cysteine proteases whose members are expressed widely in a variety of cells. We investigated the expression and possible role of the calpain isoforms m and m throughout egg activation. Both calpains were expressed in the rat egg and localized at the egg cortex as well as in the meiotic spindle. m Calpain translocated to the membrane and to the spindle area during parthenogenetic egg activation and during in vivo fertilization, upon sperm binding to the egg. The cytoskeletal protein a-spectrin (fodrin) was proteolysed by calpain during the egg-activation process, as demonstrated by specific calpain-breakdown products. Following parthenogenetic activation by ionomycin or puromycin, the calpain-selective permeable inhibitor, calpeptin, inhibited the resumption of meiosis and cortical reaction in a dosedependent manner. Calpeptin was also effective in inhibiting in vitro fertilization. These results may imply a correlation between calpain activation and mammalian egg activation at fertilization and a possible role for calpain in the cascade of cellular events leading to resumption of meiosis.

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The cortical actin-membrane cytoskeleton of unfertilized sea urchin eggs: Analysis of the spatial organization and relationship of filamentous actin, nonfilamentous actin, and egg spectrin

Cited by 63 publications

References 63 publications

Functional diversity among spectrin isoforms

Functional diversity among spectrin isoforms

Localization and dynamics of nonfilamentous actin in cultured cells [published erratum appears in J Cell Biol 1993 Nov;123(3):following 767]

Expression and possible involvement of calpain isoforms in mammalian egg activation

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