Calcium accumulation in human and sheep erythrocytes that is induced by Escherichia coli hemolysin

Jorgensen, Sally E.; Mulcahy, Paul; Wu, Grace K.; Louis, Charles F.

doi:10.1016/0041-0101(83)90277-5

Cited by 39 publications

(38 citation statements)

References 9 publications

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“…The data are in accordance with early observations of Ca 2+ requirements (57)(58)(59). However, other reports appeared to suggest that Ca 2+ was not required for the hemolytic action (60)(61)(62). Nevertheless, careful examination of the experimental procedures in the latter series of studies revealed that, in those cases, cell growth occurred in the presence of millimolar Ca 2+ concentrations.…”

Section: Ca 2+ Binding To Hlya and Membrane Lysissupporting

confidence: 79%

E. coli <FONT FACE=Symbol>a</FONT>-hemolysin: a membrane-active protein toxin

Goñi

Ostolaza

1998

Braz J Med Biol Res

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Alpha-Hemolysin is synthesized as a 1024-amino acid polypeptide, then intracellularly activated by specific fatty acylation. A second activation step takes place in the extracellular medium through binding of Ca2+ ions. Even in the absence of fatty acids and Ca2+ HlyA is an amphipathic protein, with a tendency to self-aggregation. However, Ca2+-binding appears to expose hydrophobic patches on the protein surface, facilitating both self-aggregation and irreversible insertion into membranes. The protein may somehow bind membranes in the absence of divalent cations, but only when Ca2+ (or Sr2+, or Ba2+) is bound to the toxin in aqueous suspensions, i.e., prior to its interaction with bilayers, can a-hemolysin bind irreversibly model or cell membranes in such a way that the integrity of the membrane barrier is lost, and cell or vesicle leakage ensues. Leakage is not due to the formation of proteinaceous pores, but rather to the transient disruption of the bilayer, due to the protein insertion into the outer membrane monolayer, and subsequent perturbations in the bilayer lateral tension. Protein or glycoprotein receptors for a-hemolysin may exist on the cell surface, but the toxin is also active on pure lipid bilayers

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Section: Ca 2+ Binding To Hlya and Membrane Lysissupporting

confidence: 79%

E. coli <FONT FACE=Symbol>a</FONT>-hemolysin: a membrane-active protein toxin

Goñi

Ostolaza

1998

Braz J Med Biol Res

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“…Because K ϩ quantitatively is the most important intracellular cation, this effectively means that the K ϩ efflux during the shrinkage is larger than the Na ϩ influx. This notion is supported by the large K ϩ efflux, which can be observed within 1-2 min after HlyA addition (2,5). Because HlyA is a nonselective pore, permeable to both mono-and divalent cations (6), it is unlikely to show a preference for K ϩ over Na ϩ .…”

mentioning

confidence: 49%

“…HlyA inflicts a substantial loss of K ϩ , which starts shortly after the erythrocytes have been subjected to the toxin (2,5). Part of the total cellular K ϩ loss results from lysis.…”

Section: Discussionmentioning

confidence: 99%

“…It is, however, very likely that Ca 2ϩ enters the cell through HlyA itself because it has a significant Ca 2ϩ conductance (5,20). Ca 2ϩ could also potentially enter through nonselective cation channels such as TRPC6 (21), P2X receptors (22), or via pannexin 1 channels (23), where the latter two are known to be activated upon HlyA exposure (4).…”

Section: Discussionmentioning

confidence: 99%

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Escherichia coli α-Hemolysin Triggers Shrinkage of Erythrocytes via KCa3.1 and TMEM16A Channels with Subsequent Phosphatidylserine Exposure

Skals

Jensen

Ousingsawat

et al. 2010

Journal of Biological Chemistry

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“…After different time periods, cells were removed by centrifugation, and the radioactivity remaining in the supernatants was measured by scintillation counting. Influx of the marker was calculated from the decrease in radioactivity in the supernatant [31]. The concentration of K + in the supernatants (measurement of K + efflux) was determined by flame photometry [32].…”

Section: Measurements Of Release Of K + and Atp And Uptake Of 45ca2+mentioning

confidence: 99%

Purification and characterization of a pore‐forming protein from the marine sponge Tethya lyncurium

Mangel

Leitão

Batel³

et al. 1992

European Journal of Biochemistry

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A pore-forming protein was detected and purified for the first time from a marine sponge (Tethyu lyncurium). The purified protein has a polypeptide molecular mass of 21 kDa and a pf of 6.4. Tethyu pore-forming protein (also called Tethya hemolysin) rapidly lysed erythrocytes from a variety of organisms. After binding to target membranes, the hemolysin resisted elution with EDTA, salt or solutions of low ionic strength and hence resembled an integral membrane protein. Erythrocytes could be protected from hemolysis induced by Tethya hemolysin by addition of 30 mM dextran 4 (4-6 kDa; cquivalent hydrodynamic diffusion radius, 1.75 -2.3 nm) to the extracellular medium, but not by addition of uncharged molecules of smaller size [sucrose, raffinose and poly(ethy1ene glycol) 1550; equivalent hydrodynamic diffusion radii, 0.46,0.57 and 1.2 nm, respectively]. This result indicates that hemolysin is able to form stable transmembrane pores with an effective diameter of about 2-3 nm. Treatment of osmotically protected erythrocytes with Tethya hemolysin caused a rapid efflux of intracellular K f and ATP, and a rapid influx of extracellularly added CaZ+ and sucrose. In negative-staining electron microscopy, target erythrocyte membranes exposed to purified Tethya hemolysin displayed ultrastructural lesions but without visible pores.

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Calcium accumulation in human and sheep erythrocytes that is induced by Escherichia coli hemolysin

Cited by 39 publications

References 9 publications

E. coli <FONT FACE=Symbol>a</FONT>-hemolysin: a membrane-active protein toxin

E. coli <FONT FACE=Symbol>a</FONT>-hemolysin: a membrane-active protein toxin

Escherichia coli α-Hemolysin Triggers Shrinkage of Erythrocytes via KCa3.1 and TMEM16A Channels with Subsequent Phosphatidylserine Exposure

Purification and characterization of a pore‐forming protein from the marine sponge Tethya lyncurium

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