Mechanism of Ca
            <sup>2+</sup>
            -dependent nuclear accumulation of calmodulin

Liao, Birong; Paschal, Bryce M.; Luby-Phelps, Katherine

doi:10.1073/pnas.96.11.6217

Cited by 58 publications

(54 citation statements)

References 36 publications

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“…Figure 5a shows the distribution before (left panel), and 5 minutes after (right panel), ionomycin addition. This observed translocation of CaM is consistent with previously reported nuclear enrichment of CaM in other cell types [12,27,31,32]. Figure 5b shows that the CaM translocation to the nucleus is reversible when a transient calcium signal is applied.…”

Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At supporting

confidence: 92%

“…For short calcium spikes or low-frequency repetitive calcium spikes, no equalization occurs, and nuclear amplitudes of free Ca 2+ -CaM concentration remain small compared with those in the cytosol. It is likely that such differences in nuclear versus cytosolic free Ca 2+ -CaM signals exist in many cell types, as calcium-triggered nuclear accumulation of CaM has been observed in several previous studies [12][13][14][15].…”

Section: Differential Control Of Local Free Ca 2+ -Cam Concentration mentioning

confidence: 90%

“…A photobleaching protocol [12,30,31] using either GFP (as a control) or CaM fluorescently labeled with fluorescein iso-thiocyanate (FITC-CaM) was used to measure the exchange rate of proteins between the nucleus and cytosol at low and high calcium concentrations. A previous photobleaching measurement at low calcium concentrations has shown an exchange time of CaM in the order of minutes [12].…”

Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At mentioning

confidence: 99%

“…A previous photobleaching measurement at low calcium concentrations has shown an exchange time of CaM in the order of minutes [12]. We directed a brief, 2 µm diameter, 488 nm laser pulse at the nucleus to rapidly reduce nuclear FITC-CaM or the control GFP fluorescence (Figure 4a; the pulse was applied between the first and second panels).…”

Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At mentioning

confidence: 99%

“…Third, the local concentration of Ca 2+ -CaM might be regulated by regional differences in the Ca 2+ -CaM-binding capacity. For example, as a higher CaM-binding capacity has been measured in the nucleus [12,13], receptor-triggered Ca 2+ signals should produce lower levels of free Ca 2+ -CaM concentration in the nucleus than in the cytosol.…”

Section: Introductionmentioning

confidence: 99%

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Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

et al. 2000

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Background: Many targets of calcium signaling pathways are activated or inhibited by binding the Ca 2+ -liganded form of calmodulin (Ca 2+ -CaM). Here, we test the hypothesis that local Ca 2+ -CaM-regulated signaling processes can be selectively activated by local intracellular differences in free Ca 2+ -CaM concentration.Results: Energy-transfer confocal microscopy of a fluorescent biosensor was used to measure the difference in the concentration of free Ca 2+ -CaM between nucleus and cytoplasm. Strikingly, short receptor-induced calcium spikes produced transient increases in free Ca 2+ -CaM concentration that were of markedly higher amplitude in the cytosol than in the nucleus. In contrast, prolonged increases in calcium led to equalization of the nuclear and cytosolic free Ca 2+ -CaM concentrations over a period of minutes. Photobleaching recovery and translocation measurements with fluorescently labeled CaM showed that equalization is likely to be the result of a diffusion-mediated net translocation of CaM into the nucleus. The driving force for equalization is a higher Ca 2+ -CaM-buffering capacity in the nucleus compared with the cytosol, as the direction of the free Ca 2+ -CaM concentration gradient and of CaM translocation could be reversed by expressing a Ca 2+ -CaM-binding protein at high concentration in the cytosol.Conclusions: Subcellular differences in the distribution of Ca 2+ -CaM-binding proteins can produce gradients of free Ca 2+ -CaM concentration that result in a net translocation of CaM. This provides a mechanism for dynamically regulating local free Ca 2+ -CaM concentrations, and thus the local activity of Ca 2+ -CaM targets. Free Ca 2+ -CaM signals in the nucleus remain low during brief or low-frequency calcium spikes, whereas high-frequency spikes or persistent increases in calcium cause translocation of CaM from the cytoplasm to the nucleus, resulting in similar concentrations of nuclear and cytosolic free Ca 2+ -CaM.

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Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At supporting

confidence: 92%

Section: Differential Control Of Local Free Ca 2+ -Cam Concentration mentioning

confidence: 90%

Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At mentioning

confidence: 99%

Section: Calmodulin Rapidly Exchanges Between Nucleus and Cytosol At mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

et al. 2000

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Distribution of Adenylyl Cyclases in the Rat Ovary by Immunofluorescence Microscopy

Bagavandoss

Grimshaw

2012

The Anatomical Record

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In the mammalian ovary both gonadotropins and local cytokines, acting through G-protein coupled receptors, govern the physiology of the ovary in part by regulating the cyclic adenosine 3 0 ,5 0 -monophosphate via adenylyl cyclases. The nine transmembrane adenylyl cyclases and a soluble adenylyl cyclase are regulated by a diversity of ligands. In this study we have examined the rat ovaries, prior to and subsequent to gonadotropin treatment, for the presence of different transmembrane adenylyl cyclases by indirect immunofluorescence microscopy. Adenylyl cyclase I immunoreactivity was observed in the nuclei of oocytes in preantral and antral follicles along with some staining in granulosa cells. Equine chorionic gonadotropin injection increased adenylyl cyclase I staining in granulosa cells. Adenylyl cyclase I staining was also observed in luteal and endothelial cells. Adenylyl cyclase II was observed throughout the ovary, including granulosa cells and the ovarian surface epithelium. Adenylyl cyclase II staining was also found to increase in granulosa cells after equine chorionic gonadotropin injection. Adenylyl cyclase III was distributed primarily in theca and smooth muscle cells of arterioles, with faint staining in the oocytes of equine chorionic gonadotropin-injected ovaries. Adenylyl cyclase IV staining was present throughout the ovary, including the nuclei of oocytes. Adenylyl cyclase VIII staining in granulosa cells increased subsequent to equine chorionic gonadotropin injection and remained in luteal cells. Our study reveals the redundancy of adenylyl cyclases present in the rat ovary and, therefore, implies potential regulation of follicular and corpus luteum physiology by cyclic adenosine 3 0 ,5 0 -monophosphate generated through distinct adenylyl cyclases.

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Calcyclin (S100A6) regulates pulmonary fibroblast proliferation, morphology, and cytoskeletal organization in vitro

Breen

Tang

2003

J of Cellular Biochemistry

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Calcyclin (S100A6) is a member of the S100A family of calcium binding proteins. While the precise function of calcyclin is unknown, calcyclin expression is associated with cell proliferation and calcyclin is expressed in several types of cancer phenotypes. In the present study, the functional role of calcyclin was further elucidated in pulmonary fibroblasts. Antisense S100A6 RNA expression inhibited serum and mechanical strain-induced fibroblast proliferation. This attenuated proliferative response was accompanied by a flattened, spread cell morphology, and disruption of tropomyosin labeled microfilaments. Changes in cytoskeletal organization did not correspond with a decrease in tropomyosin levels. These observations suggest a role for calcyclin in modulating calcium dependent signaling events that regulate progression through the cell cycle. J. Cell. Biochem. 88: 848-854, 2003.

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Mechanism of Ca ²⁺ -dependent nuclear accumulation of calmodulin

Cited by 58 publications

References 36 publications

Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

Distribution of Adenylyl Cyclases in the Rat Ovary by Immunofluorescence Microscopy

Calcyclin (S100A6) regulates pulmonary fibroblast proliferation, morphology, and cytoskeletal organization in vitro

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Mechanism of Ca 2+ -dependent nuclear accumulation of calmodulin

Cited by 58 publications

References 36 publications

Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor

Distribution of Adenylyl Cyclases in the Rat Ovary by Immunofluorescence Microscopy

Calcyclin (S100A6) regulates pulmonary fibroblast proliferation, morphology, and cytoskeletal organization in vitro

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Mechanism of Ca ²⁺ -dependent nuclear accumulation of calmodulin