scholarly journals SMRT ‐mediated co‐shuttling enables export of class II a HDAC s independent of their CaM kinase phosphorylation sites

2012 ◽  
Vol 124 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Francesc X. Soriano ◽  
Sangeeta Chawla ◽  
Paul Skehel ◽  
Giles E. Hardingham
2008 ◽  
Vol 31 (4) ◽  
pp. 22
Author(s):  
Jonathan So ◽  
Kelly Elder ◽  
Anna Dai ◽  
Claus Jorgensen ◽  
Rune Linding ◽  
...  

Networks of kinases play a role in the transmission and integration of signals from the membrane to the nucleus. We aim to elucidate kinase phosphorylation and interaction partners in these networks through the immuno-precipitation and mass spectrometric analysis of a representative set of 100 Flag-tagged kinases stably expressed in human colorectal cancer cells. The goal is to generate a comprehensive set of interactions and dynamic phosphorylation sites which correlate with cell phenotypes such as apoptosis and proliferation. The techniques of mass-spectrometry have allowed for the identification of proteins and their phosphorylation sites in complex samples. Various labeling methods such as iTRAQ has enabled the relative quantification of these sites as afunction of time (White et al. PNAS, 2007). However, kinases usually work in the context of particular signaling stimuli. We aim to characterize the role of these over-expressed kinases in the context of Trail-induced apoptosis. This isparticularly relevant to tumorigenesis in that many cancers are resistant to apoptosis and recombinant Trail therapies are currently undergoing clinical trials. We present assays to correlate the proliferative ability and sensitivity to apoptosis of various stable cell lines with kinase expression levels through flow cytometry. We also present efforts to trace downstream signaling through the monitoring of MAP kinase phosphorylation using a high-throughput bead array.


2003 ◽  
pp. 153-161
Author(s):  
Joel J. Ellis ◽  
Thomas G. Valencia ◽  
Hong Zeng ◽  
L. Don Roberts ◽  
Rebecca A. Deaton ◽  
...  

2009 ◽  
Vol 20 (1) ◽  
pp. 134-145 ◽  
Author(s):  
Aviva E. Diamond ◽  
Jae-Sook Park ◽  
Ichiro Inoue ◽  
Hiroyuki Tachikawa ◽  
Aaron M. Neiman

Ascospore formation in yeast is accomplished through a cell division in which daughter nuclei are engulfed by newly formed plasma membranes, termed prospore membranes. Closure of the prospore membrane must be coordinated with the end of meiosis II to ensure proper cell division. AMA1 encodes a meiosis-specific activator of the anaphase promoting complex (APC). The activity of APCAma1is inhibited before meiosis II, but the substrates specifically targeted for degradation by Ama1 at the end of meiosis are unknown. We show here that ama1Δ mutants are defective in prospore membrane closure. Ssp1, a protein found at the leading edge of the prospore membrane, is stabilized in ama1Δ mutants. Inactivation of a conditional form of Ssp1 can partially rescue the sporulation defect of the ama1Δ mutant, indicating that an essential function of Ama1 is to lead to the removal of Ssp1. Depletion of Cdc15 causes a defect in meiotic exit. We find that prospore membrane closure is also defective in Cdc15 and that this defect can be overcome by expression of a form of Ama1 in which multiple consensus cyclin-dependent kinase phosphorylation sites have been mutated. These results demonstrate that APCAma1functions to coordinate the exit from meiosis II with cytokinesis.


2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
S. H. Choi ◽  
B. H. Lee ◽  
S. H. Hwang ◽  
H. J. Kim ◽  
S. M. Lee ◽  
...  

Gintonin is a unique lysophosphatidic acid (LPA) receptor ligand found inPanax ginseng. Gintonin induces transient [Ca2+]ithrough G protein-coupled LPA receptors. Large-conductance Ca2+-activated K+(BKCa) channels are expressed in blood vessels and neurons and play important roles in blood vessel relaxation and attenuation of neuronal excitability. BKCachannels are activated by transient [Ca2+]iand are regulated by various Ca2+-dependent kinases. We investigated the molecular mechanisms of BKCachannel activation by gintonin. BKCachannels are heterologously expressed inXenopus oocytes. Gintonin treatment induced BKCachannel activation in oocytes expressing the BKCachannelαsubunit in a concentration-dependent manner (EC50= 0.71 ± 0.08 µg/mL). Gintonin-mediated BKCachannel activation was blocked by a PKC inhibitor, calphostin, and by the calmodulin inhibitor, calmidazolium. Site-directed mutations in BKCachannels targeting CaM kinase II or PKC phosphorylation sites but not PKA phosphorylation sites attenuated gintonin action. Mutations in the Ca2+bowl and the regulator of K+conductance (RCK) site also blocked gintonin action. These results indicate that gintonin-mediated BKCachannel activations are achieved through LPA1 receptor-phospholipase C-IP3-Ca2+-PKC-calmodulin-CaM kinase II pathways and calcium binding to the Ca2+bowl and RCK domain. Gintonin could be a novel contributor against blood vessel constriction and over-excitation of neurons.


2021 ◽  
Author(s):  
Alejandro Padilla

The large families of amastins from Leishmania donovani, L. infantum, L. major, L. braziliensis and Trypanosoma cruzi are strongly associated with the evolution of intracellular parasitism of rich cells in human MHC.1 molecules such as the macrophages, dendritic cells, and Langerhans cells by these parasites, recognize the MHC-1 molecules as host receptor. The internalization and transport of the paraste in the cytoplas of infected cell is facilitated by the MHC-1 recycle and endosome formation drag and transport the parasite in the cytoplasm of infected cell. The microbody amastins participate as coreceptor potency the infection, the tropism of L. major and L. braziliensis by the cells from the skin is facilitated by two molecular interactions, the first molecular interaction is faclitated by the amastins interact the human MHC-1 molecules, and the second molecular interaction is facilitated by the numerous microbody amastins; which also participate in the biogenesis of the small prasitophorous vcuole from L. major, and large parasitophorous vacuole from L. braziliensis. All amastins from these parasites developed deactivation domains, in different grade L. donovani develop an amastin surface coat specialized in deactivation of infected macrophages heavily glycosylated developed 38 amastins with 38 glycosylation Asp. N-Glycosylation sites and 45 N-glucosamina glycosylation sites, whereas L. infantum, L. major and L. braziliensis developed one half of glycosylated amastins in asparagine N-glycosylation sites, and T. cruzi did not developed none glycosylated amastin. The amastins surface coat from L. donovani is rich in phosphorylation sites, developed 45 amastins with 45 casein kinase II phosphorylations sites, and 48 amastins with 48 protein kinase phosphorylation sites. L. infantum, L. braziliensis, and T. cruzi developed 32, 42, and 8 amastins, with 94, 114, 21 casein kinase II phosphorylation sites; in similar way developed 35, 38, 11 amastins with 89, 78, and 22 protein kinase phosphorylation sites. The family of amastins from L. donovani develop 137 phosphoserines. and 128 phosphothreonine, L. major developed 14 phosphoserine and 4 phosphothreonine; L. infantum 1 phophoserine and 7 phosphothreonine; L. braziliensis did not developed phosphoserine and phosphothreonine and T. cruzi 4 phosphoserine and 4 phosphothreonine. The results show that amastin surface coat is equiped with numerous phosphorylations sites atractive for phosphohrylases from the infected host contribute with the dephosphorylation and deactivation of infectetd host cells. The amastins from L. major develop a membrane amastin with laminin G domain, which can interact with the collagen and heparin sulfate proteoglycan sites from the extracellular matrix of the skin tissue. Furthermore develop 14 amastins with tyrosine sulfation site, evade the activation of receptor of chemokines and the activation of the immune response by chemokines. There is an alternative mechanism of polarization of the immune response from protective TH1 to non protective TH2. The parasite nutrition is mediated by amastins that dissimilate the MHC-1 molecules and other subsets of proteins, the dissimilation products can be translocated through of the parasite cell membrane and employed as nutrient source.


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