Bile Acids Induce Ca2+Release from Both the Endoplasmic Reticulum and Acidic Intracellular Calcium Stores through Activation of Inositol Trisphosphate Receptors and Ryanodine Receptors

We have investigated the subcellular distribution and identity of inositol trisphosphate (InsP3)-sensitive calcium stores in living Limulus ventral photoreceptor cells, where light and InsP3 are known to raise intracellular calcium. We injected ventral photoreceptor cells with the photoprotein aequorin and viewed its luminescence with an image intensifier. InsP3 only elicited detectable aequorin luminescence when injected into the light-sensitive rhabdomeral (R)-lobe where aequorin luminescence induced by light was also confined. Calcium stores released by light and InsP3 are therefore localized to the R-lobe. Within the R-lobe, InsP3-induced aequorin luminescence was further confined around the injection site, due to rapid dilution and/or degradation of injected InsP3. Prominent cisternae of smooth endoplasmic reticulum are uniquely localized within the cell beneath the microvillar surface of the R-lobe (Calman, B., and S. Chamberlain, 1982, J. Gen. Physiol., 80:839-862). These cisternae are the probable site of InsP3 action.

Download Full-text

Presenilin-1 and intracellular calcium stores regulate neuronal glutamate uptake

Journal of Neurochemistry ◽

10.1046/j.1471-4159.2003.02279.x ◽

2004 ◽

Vol 88 (6) ◽

pp. 1361-1372 ◽

Cited By ~ 19

Author(s):

Yaxiong Yang ◽

Gregory A. Kinney ◽

William J. Spain ◽

John C. S. Breitner ◽

David G. Cook

Keyword(s):

Intracellular Calcium ◽

Glutamate Uptake ◽

Presenilin 1 ◽

Calcium Stores ◽

Intracellular Calcium Stores

Download Full-text

Multiple Receptor Interactions Trigger Release of Membrane and Intracellular Calcium Stores Critical for Herpes Simplex Virus Entry

Molecular Biology of the Cell ◽

10.1091/mbc.e07-01-0062 ◽

2007 ◽

Vol 18 (8) ◽

pp. 3119-3130 ◽

Cited By ~ 45

Author(s):

Natalia Cheshenko ◽

Wen Liu ◽

Lisa M. Satlin ◽

Betsy C. Herold

Keyword(s):

Herpes Simplex ◽

Intracellular Calcium ◽

Viral Entry ◽

Calcium Stores ◽

Calcium Response ◽

Herpes Simplex Viruses ◽

Intracellular Calcium Stores ◽

Viral Binding ◽

Glycoprotein H ◽

Simplex Virus

Herpes simplex viruses (HSV) harness cellular calcium signaling pathways to facilitate viral entry. Confocal microscopy and small interfering RNA (siRNA) were used to identify the source of the calcium and to dissect the requisite viral–cell interactions. Binding of HSV to human epithelial cells induced no calcium response, but shifting the cells to temperatures permissive for penetration triggered increases in plasma membrane calcium followed by a global release of intracellular calcium. Transfection with siRNA targeting the proteoglycan syndecan-2 blocked viral binding and abrogated any calcium response. Transfection with siRNA targeting nectin-1, a glycoprotein D receptor, also prevented both membrane and intracellular calcium responses. In contrast, the membrane response was preserved after transfection with siRNA targeting integrinαv, a novel glycoprotein H receptor. The membrane response, however, was not sufficient for viral entry, which required interactions with integrinαv and release of inositol-triphosphate receptor-dependent intracellular calcium stores. Thus, calcium plays a critical, complex role in HSV entry.

Download Full-text