Opposing effects of PKCα and PKCε on basolateral  membrane dynamics in intestinal epithelia

Song, Jae Chul; Rangachari, P. K.; Matthews, Jeffrey B.

doi:10.1152/ajpcell.00105.2002

Cited by 44 publications

(39 citation statements)

References 35 publications

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“…On one hand, at the beginning of the process, when the cPKCs were present in the cytoplasm, their roles in the control of GVBD differed according to the isoform: for instance, PKC-α was not involved in this process whereas PKC-βI and PKC-γ prevented GVBD and PKC-βII promoted it. Our data are consistent with several reports describing the antagonistic effects of various cPKC isoforms on the regulation of biological functions in other cell types (Chen and Mochly-Rosen, 2001;Efendiev et al, 1999;Gusovsky and Gutkind, 1991;Rosales et al, 1998;Song et al, 2002). For example, for the cPKC family, PKC-βI and PKC-βII have been shown to have opposite effects in vascular smooth muscle cell proliferation (Yamamoto et al, 1998).…”

Section: Cytoplasmic and Nuclear Cpkc And Meiosis Resumptionsupporting

confidence: 92%

Regulation of spontaneous meiosis resumption in mouse oocytes by various conventional PKC isozymes depends on cellular compartmentalization

Avazeri

Courtot

Lefèvre

2004

Journal of Cell Science

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In this study, we investigated the spatio-temporal distribution of conventional protein kinases C (cPKC) isoforms PKC-α, PKC-βI, PKC-βII and PKC-γ in mouse oocytes. The cPKCs were present in the cytoplasm at the start of the process and migrated to the nucleus (or germinal vesicle) before germinal vesicle breakdown, except for PKC-γ which remained cytoplasmic. In both compartments, the fully phosphorylated form corresponding to the `mature' enzyme was revealed for PKC-α, PKC-βI and PKC-βII. Microinjection of specific antibodies against each isozyme in one or the other cell compartment at different times of the meiotic process, permitted us to observe the following: (1) When located in the cytoplasm at the beginning of the process, PKC-α is not implicated in germinal vesicle breakdown, PKC-βI and PKC-γ are involved in maintaining the meiotic arrest, and PKC-βII plays a role in meiosis reinitiation. Furthermore, just before germinal vesicle breakdown, these cytoplasmic cPKCs were no longer implicated. (2) When located in the germinal vesicle, PKC-α, PKC-βI and PKC-βII are involved in meiosis reinitiation. Our data highlight not only the importance of the nuclear pathways in the cell cycle progression, but also their independence of the cytoplasmic ones. Further investigations are however necessary to discover the molecular targets of these cPKCs to better understand the links with the cell cycle progression.

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Section: Cytoplasmic and Nuclear Cpkc And Meiosis Resumptionsupporting

confidence: 92%

Regulation of spontaneous meiosis resumption in mouse oocytes by various conventional PKC isozymes depends on cellular compartmentalization

Avazeri

Courtot

Lefèvre

2004

Journal of Cell Science

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“…Interestingly, in contrast to PKCa expression, the protein level of PKCe showed an inverse relationship to that of Ets1 ( Figure 2d). As has been reported for intestinal epithelial cells (Song et al, 2002), PKCa and PKCe may have opposing effects in cancer cells. Collectively, these data suggest that, in different types of cancer cells, PKCa regulates the expression of Ets1.…”

Section: Suppression Of Endogenous Pkca Expression Results In Downregsupporting

confidence: 59%

Ets1 is an effector of protein kinase Cα in cancer cells

Vetter¹,

Blumenthal

Lindemann

et al. 2004

Oncogene

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PKCa and Ets1 are both associated with breast cancer progression. Our previous studies suggested that these proteins are likely to functionally interact with one another. Here, we show that attenuation of endogenous PKCa expression (siPa) by RNA interference leads to reduced Ets1 protein expression in a variety of cancer cells. Pulse-chase experiments and treatment with proteasome inhibitor MG-132 revealed that siPa interferes with both Ets1 protein synthesis and stability. The effect of siPa on Ets1 expression could be partially prevented by KN-93, suggesting that calcium/calmodulin-dependent kinase II (CaMKII), a modulator of Ets1 activity, may play a role in PKCa-dependent Ets1 regulation. In contrast, Ets1-regulating kinases ERK1/ 2 were not found to be involved in this process. To assess the importance of the PKCa/Ets1 interaction, we compared the biological responses of MDA-MB-231 cells to PKCa-and Ets1-specific siRNAs (siE1). While only siPa induced changes in cellular morphology and anchorage-independent growth, both siRNAs similarly affected cellular responses to the antitumor drug mithramycin A and to UV light. Microarray analyses further showed that the expression of a certain set of genes was equally affected by siPa and siE1. The data suggest that Ets1 serves as an effector for PKCa to fulfil certain functions in cancer cells.

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“…systems, including glioma cell migration (26) and basolateral membrane dynamics in intestinal epithelia (27). However, the current study is the first to demonstrate that PKC␣ and PKC⑀ can oppose one another through their opposite effects on the MEK/ERK signaling cascade.…”

Section: Discussionmentioning

confidence: 60%

Opposing Effects of Protein Kinase Cα and Protein Kinase Cϵ on Collagen Expression by Human Lung Fibroblasts Are Mediated via MEK/ERK and Caveolin-1 Signaling

Tourkina

Göőz

Pannu

et al. 2005

Journal of Biological Chemistry

114

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The roles of MEK, ERK, the ⑀ and ␣ isoforms of protein kinase C (PKC), and caveolin-1 in regulating collagen expression were studied in normal lung fibroblasts. Knocking down caveolin-1 gave particularly striking results. A 70% decrease caused a 5-fold increase in MEK/ ERK activation and collagen expression. The combined data reveal a branched signaling pathway. In its central portion MEK activates ERK, leading to increased collagen expression. Two branches converge on MEK/ERK. In one, increased PKC⑀ leads to MEK/ERK activation. In another, increased PKC␣ induces caveolin-1 expression, which in turn inhibits MEK/ERK activation and collagen expression. Lung fibroblasts from scleroderma patients with pulmonary fibrosis showed altered signaling. Consistent with their overexpression of collagen, scleroderma lung fibroblasts contain more activated MEK/ERK and less caveolin-1 than normal lung fibroblasts. Because cutaneous fibrosis is the hallmark of scleroderma, we also studied dermal fibroblasts. As in lung, there was more activated MEK/ERK in cells from scleroderma patients than in control cells, and MEK inhibition decreased collagen expression. However, the distinctive levels of PKC⑀, PKC␣, and caveolin-1 in lung and dermal fibroblasts from scleroderma patients and control subjects indicate that the links between these signaling proteins and MEK/ERK must function differently in the four cell types. Finally, we confirmed the relevance of these signaling cascades in vivo. The combined results demonstrate that a branched signaling pathway involving MEK, ERK, PKC⑀, PKC␣, and caveolin-1 regulates collagen expression in normal lung tissue and is perturbed during fibrosis.

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Opposing effects of PKCα and PKCε on basolateral membrane dynamics in intestinal epithelia

Cited by 44 publications

References 35 publications

Regulation of spontaneous meiosis resumption in mouse oocytes by various conventional PKC isozymes depends on cellular compartmentalization

Regulation of spontaneous meiosis resumption in mouse oocytes by various conventional PKC isozymes depends on cellular compartmentalization

Ets1 is an effector of protein kinase Cα in cancer cells

Opposing Effects of Protein Kinase Cα and Protein Kinase Cϵ on Collagen Expression by Human Lung Fibroblasts Are Mediated via MEK/ERK and Caveolin-1 Signaling

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