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Solid tumors: biochemical overview and mechanical modeling
Published in Benjamin Loret, Fernando M. F. Simões, Biomechanical Aspects of Soft Tissues, 2017
Benjamin Loret, Fernando M. F. Simões
– receptors with one segment which have a tyrosine-kinase activity and that can bind growth factors and hormones that stimulate growth;– some proteins called G proteins that bind to GTP (guanine tri-phosphate). In normal cells, the external signal associated with a 7 segment receptor uses a G protein which activates an effector protein and phosphorylates GTP in GDP. The main G proteins are the intramembrane Ras proteins (H-ras, K-Ras, N-Ras) that transmit the phosphorylation through the cytoplasmic Raf;– many oncogenic proteins are protein kinases. Protein kinases stabilize the intracellular activity by phosphorylating certain proteins. Protein phosphatases dephosphorylate these proteins. Protein kinases may be activated by cAMP (they are then called PK-A), by cGMP (PK-G), by diacylglycerol (PK-C) and others are Ca2+/calmodulin-dependent. According to the nature of the amino-acid residues, one distinguishes tyrosine kinases and serine-threosine kinases. Some protein kinases are soluble, others are linked to the sarcolemma;– some factors of transcription activated by liposoluble hormones (steroids);– anti-oncogenes;– after the cascades of kinases and phosphatases, a family of proteins called MAP (mitogen activated proteins) enters the nucleus and phosphorylates the genes of DNA transcription.
A review of algal toxin exposures on reserved federal lands and among trust species in the United States
Published in Critical Reviews in Environmental Science and Technology, 2022
Zachary R. Laughrey, Victoria G. Christensen, Robert J. Dusek, Sarena Senegal, Julia S. Lankton, Tracy A. Ziegler, Lee C. Jones, Daniel K. Jones, Brianna M. Williams, Stephanie Gordon, Gerald A. Clyde, Erich B. Emery, Keith A. Loftin
Microcystins are produced by a variety of cyanobacteria (Supplemental Table 1) and act as protein phosphatase inhibitors. Microcystin exposure has been documented in 8 Trust species including two species of marine mammals, five species of migratory birds, and one fish in eight states (Supplementary Tables 8, 9, and 10). Trust species can be exposed to microcystin by eating the cyanobacteria directly or by consuming a prey species that have accumulated the toxin. Microcystins act primarily as a hepatotoxins but may also affect other bodily systems including heart, brain, lungs, and gastrointestinal tract. Depending on the species, the most predominant clinical signs of acute exposure to microcystin are gastrointestinal (Massey et al., 2018).
Involvement of MAPK/ERK1/2 pathway in microcystin-induced microfilament reorganization in HL7702 hepatocytes
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Fei Yang, Cong Wen, Shuilin Zheng, Shu Yang, Jihua Chen, Xiangling Feng
Protein phosphatase 2A (PP2A) activity was measured according to manufacturer’s instructions (Promega, USA). After incubation with MC-LR, cells were collected, lysed to obtain the protein fraction, and endogenous phosphates eliminated as described by Yang et al. (2018). The cellular protein samples were added to the mixture solution containing 1 mM phosphopeptide substrate and incubated at 37°C for 30 min. Subsequently, 50 µl molybdate dye-additive mixture was added to stop the reaction. The absorbance was measured at 630 nm after 15 min, and PP2A activity expressed as pmol/µg protein/min.
MicroRNA expression profiling involved in MC-LR-induced hepatotoxicity using high-throughput sequencing analysis
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Shu Yang, Lv Chen, Cong Wen, Xian Zhang, Xiangling Feng, Fei Yang
Protein phosphatase 2A (PP2A) activity was assayed according to manufacturer’s instructions (Promega, USA). After incubation with MC-LR, cells were collected, lysed to obtain the protein fraction, and endogenous phosphates discarded. The cellular protein samples were added to the mixture containing 5 μl 1 mM phosphopeptide substrate. After 30 min incubation at 37°C, 50 μl of molybdate dye-additive mixture was added to stop the reaction. Absorbance was read at 630 nm after 15 min, and PP2A activity expressed as pmol/μg protein/min.