scholarly journals PKCα: a versatile key for decoding the cellular calcium toolkit

2006 ◽  
Vol 174 (4) ◽  
pp. 521-533 ◽  
Author(s):  
Gregor Reither ◽  
Michael Schaefer ◽  
Peter Lipp
Keyword(s):  
Signal Transduction ◽  
Protein Kinases ◽  
Essential Role ◽  
Flash Photolysis ◽  
Slow Phase ◽  
C2 Domain ◽  
Membrane Interactions ◽  
Binding Region ◽  
C2 Domains ◽  
Cellular Calcium

Conventional protein kinases C (cPKCs) play an essential role in signal transduction and are believed to integrate both global Ca2+ transients and diacylglycerol signals. We provide evidence that PKCα is a ubiquitous readout sensor for the cellular Ca2+ toolkit, including highly restricted elementary Ca2+ release. Threshold stimulations of cells with Ca2+-mobilizing agonists resulted in PKCα translocation events with limited spatial spreads (<4 μm) comprising two groups of lifetimes; brief events (400–1,500 ms) exclusively mediated by Ca2+–C2 domain membrane interactions and long-lasting events (>4 s) resulting from longer DAG-C1a domain–mediated membrane interactions. Although upon uncaging NP-EGTA, which is a caged Ca2+ compound, WT-PKCα displayed rapid membrane translocations within <250 ms, PKCα constructs with C2 domains mutated in their Ca2+-binding region lacked any Ca2+-dependent translocation. Flash photolysis of diazo-2, a photosensitive caged Ca2+ buffer, revealed a biphasic membrane dissociation (slow and fast period) of WT-PKCα. The slow phase was absent in cells expressing PKCα-constructs containing mutated C1a-domains with largely reduced DAG binding. Thus, two groups of PKCα membrane interactions coexist; C2- and C1a-mediated interactions with different lifetimes but rapid interconversion. We conclude that PKCα can readout very fast and, spatially and temporally, very complex cellular Ca2+ signals. Therefore, cPKCs are important transducers for the ubiquitous cellular Ca2+ signaling toolkit.

scholarly journals The C2A-C2B Linker Defines the High Affinity Ca2+ Binding Mode of Rabphilin-3A

2006 ◽  
Vol 282 (7) ◽  
pp. 5015-5025 ◽  
Author(s):  
Pierre Montaville ◽  
Christine Schlicker ◽  
Andrei Leonov ◽  
Markus Zweckstetter ◽  
George M. Sheldrick ◽  
...  
Keyword(s):  
Binding Mode ◽  
Bound State ◽  
C2 Domain ◽  
Binding Assays ◽  
Host Proteins ◽  
Binding Properties ◽  
C2 Domains ◽  
Phospholipid Binding ◽  
Acidic Residues ◽  
Structural Base

The Ca2+ binding properties of C2 domains are essential for the function of their host proteins. We present here the first crystal structures showing an unexpected Ca2+ binding mode of the C2B domain of rabphilin-3A in atomic detail. Acidic residues from the linker region between the C2A and C2B domains of rabphilin-3A interact with the Ca2+-binding region of the C2B domain. Because of these interactions, the coordination sphere of the two bound Ca2+ ions is almost complete. Mutation of these acidic residues to alanine resulted in a 10-fold decrease in the intrinsic Ca2+ binding affinity of the C2B domain. Using NMR spectroscopy, we show that this interaction occurred only in the Ca2+-bound state of the C2B domain. In addition, this Ca2+ binding mode was maintained in the C2 domain tandem fragment. In NMR-based liposome binding assays, the linker was not released upon phospholipid binding. Therefore, this unprecedented Ca2+ binding mode not only shows how a C2 domain increases its intrinsic Ca2+ affinity, but also provides the structural base for an atypical protein-Ca2+-phospholipid binding mode of rabphilin-3A.

scholarly journals Signal transduction: Gyrating protein kinases

1999 ◽  
Vol 9 (10) ◽  
pp. R364-R367 ◽  
Author(s):  
Jeff Stock
Keyword(s):  
Signal Transduction ◽  
Protein Kinases

scholarly journals The TOR Signal Transduction Cascade Controls Cellular Differentiation in Response to Nutrients

2001 ◽  
Vol 12 (12) ◽  
pp. 4103-4113 ◽  
Author(s):  
N. Shane Cutler ◽  
Xuewen Pan ◽  
Joseph Heitman ◽  
Maria E. Cardenas
Keyword(s):  
Signal Transduction ◽  
Protein Kinases ◽  
Protein Phosphatase ◽  
Nutrient Sensing ◽  
Yeast Cells ◽  
Regulatory Subunit ◽  
Growth Defect ◽  
Tor Pathway ◽  
Pseudohyphal Growth ◽  
Pseudohyphal Differentiation

Rapamycin binds and inhibits the Tor protein kinases, which function in a nutrient-sensing signal transduction pathway that has been conserved from the yeast Saccharomyces cerevisiaeto humans. In yeast cells, the Tor pathway has been implicated in regulating cellular responses to nutrients, including proliferation, translation, transcription, autophagy, and ribosome biogenesis. We report here that rapamycin inhibits pseudohyphal filamentous differentiation of S. cerevisiae in response to nitrogen limitation. Overexpression of Tap42, a protein phosphatase regulatory subunit, restored pseudohyphal growth in cells exposed to rapamycin. The tap42-11 mutation compromised pseudohyphal differentiation and rendered it resistant to rapamycin. Cells lacking the Tap42-regulated protein phosphatase Sit4 exhibited a pseudohyphal growth defect and were markedly hypersensitive to rapamycin. Mutations in other Tap42-regulated phosphatases had no effect on pseudohyphal differentiation. Our findings support a model in which pseudohyphal differentiation is controlled by a nutrient-sensing pathway involving the Tor protein kinases and the Tap42–Sit4 protein phosphatase. Activation of the MAP kinase or cAMP pathways, or mutation of the Sok2 repressor, restored filamentation in rapamycin treated cells, supporting models in which the Tor pathway acts in parallel with these known pathways. Filamentous differentiation of diverse fungi was also blocked by rapamycin, demonstrating that the Tor signaling cascade plays a conserved role in regulating filamentous differentiation in response to nutrients.

scholarly journals TC2N: A Novel Vital Oncogene or Tumor Suppressor Gene In Cancers

2021 ◽  
Vol 12 ◽  
Author(s):  
Hanyang Li ◽  
He Fang ◽  
Li Chang ◽  
Shuang Qiu ◽  
Xiaojun Ren ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Tumor Suppressor Gene ◽  
Protein Interactions ◽  
Malignant Tumors ◽  
Suppressor Gene ◽  
C2 Domain ◽  
Protein Protein Interactions ◽  
C2 Domains ◽  
Different Types ◽  
Shock Proteins

Several C2 domain-containing proteins play key roles in tumorigenesis, signal transduction, and mediating protein–protein interactions. Tandem C2 domains nuclear protein (TC2N) is a tandem C2 domain-containing protein that is differentially expressed in several types of cancers and is closely associated with tumorigenesis and tumor progression. Notably, TC2N has been identified as an oncogene in lung and gastric cancer but as a tumor suppressor gene in breast cancer. Recently, a large number of tumor-associated antigens (TAAs), such as heat shock proteins, alpha-fetoprotein, and carcinoembryonic antigen, have been identified in a variety of malignant tumors. Differences in the expression levels of TAAs between cancer cells and normal cells have led to these antigens being investigated as diagnostic and prognostic biomarkers and as novel targets in cancer treatment. In this review, we summarize the clinical characteristics of TC2N-positive cancers and potential mechanisms of action of TC2N in the occurrence and development of specific cancers. This article provides an exploration of TC2N as a potential target for the diagnosis and treatment of different types of cancers.

Involvement of cyclic AMP-dependent protein kinases in the signal transduction pathway for interleukin-1

1990 ◽  
Vol 10 (7) ◽  
pp. 3824-3827
Author(s):  
M Chedid ◽  
S B Mizel
Keyword(s):  
Signal Transduction ◽  
Cyclic Amp ◽  
Protein Kinases ◽  
Gene Transcription ◽  
Interleukin 1 ◽  
Signal Transduction Pathway ◽  
Cell Types ◽  
Specific Protein ◽  
Transduction Pathway ◽  
Dependent Protein

Expression of a highly specific protein inhibitor for cyclic AMP-dependent protein kinases in interleukin-1 (IL-1)-responsive cells blocked IL-1-induced gene transcription that was driven by the kappa immunoglobulin enhancer or the human immunodeficiency virus long terminal repeat. This inhibitor did not affect protein kinase C-mediated gene transcription, suggesting that cyclic AMP-dependent protein kinases are involved in the signal transduction pathway for IL-1 in a number of responsive cell types.

scholarly journals Mitogen-Activated Protein Kinases: Functions in Signal Transduction and Human Diseases

2019 ◽  
Vol 20 (19) ◽  
pp. 4844 ◽  
Author(s):  
Ritva Tikkanen ◽  
David J. Nikolic-Paterson
Keyword(s):  
Signal Transduction ◽  
Growth Factors ◽  
Protein Kinases ◽  
Human Diseases ◽  
Mitogen Activated Protein Kinases ◽  
Mitogen Activated Protein

Mitogen-activated protein kinases (MAPKs) are involved in signaling processes induced by various stimuli, such as growth factors, stress, or even autoantibodies [...]

scholarly journals Two Calcium-Dependent Protein Kinases, CPK4 and CPK11, Regulate Abscisic Acid Signal Transduction in Arabidopsis

2007 ◽  
Vol 19 (10) ◽  
pp. 3019-3036 ◽  
Author(s):  
Sai-Yong Zhu ◽  
Xiang-Chun Yu ◽  
Xiao-Jing Wang ◽  
Rui Zhao ◽  
Yan Li ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Abscisic Acid ◽  
Protein Kinases ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinases
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