Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.107 (DAT)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alpha-synuclein modulates dopamine homeostasis in dopamine-producing neurons of substantia nigra, partly through regulation of human dopamine transporter (hDAT) activity. To identify the underlying mechanisms, we disrupted the modulation of hDAT activity by wild-type (wt) alpha-synuclein, and its familial Parkinson's disease linked mutants A30P and A53T, by mild trypsinization (0.1%, 30 s) of Ltk(-) cotransfected cells. Trypsin completely reversed the attenuation of hDAT function mediated by wt and the A30P mutant. In A53T coexpressing cells, where DAT activity is not downregulated, trypsinization did not induce any changes. These effects of trypsin were mimicked by collagenase I and Dispase (0.1%, 1 min each) but not by chymotrypsin, Pronase, or papain (0.1%, up to 2 min each). Trypsin increased dopamine uptake in rat primary mesencephalic neurons, suggesting that DAT activity is also subjected to modulation by alpha-synuclein in these neurons that endogenously coexpress both proteins. In trypsinized cells, dopamine accelerated both production of reactive oxygen species and cell death in hDAT and wt or A30P, but not A53T, coexpressing cells, compared to nontrypsinized cells. Paradoxically, trypsin increased the protein-protein interactions between the synuclein variants and hDAT, without any noticeable proteolysis of these proteins. hDAT-alpha-synuclein protein-protein interactions occurred through residues 58-107 (NAC domain) of the alpha-synuclein variants and residues 598-620 of the carboxy-terminal tail of hDAT, in both trypsinized and nontrypsinized cells. Confocal microscopy and biotinylation studies show that, in cells expressing the wt or A30P variants, but not the A53T mutant, hDAT is sequestered away from the plasma membrane into the cytoplasm, an effect that is reversed by trypsin. These results show that alpha-synuclein modulates hDAT function through trafficking of the transporter in a process that can be disrupted by trypsin.
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PMID:Trypsin disrupts the trafficking of the human dopamine transporter by alpha-synuclein and its A30P mutant. 1475 60

Blood samples from a 10-month-old male infant requiring transfusion were found to contain an allomtibody reacting at 37 degrees C in saline, by indirect antiglobulin test (IAT), and with a manual polybrene technique. Preliminary results suggested anti-D and another weaker reacting antibody, but the patient had been previously transfused with only D- blood. His serum reacted more weakly by IAT against red cells treated with 0.2M dithiothreitol (DTT), and one D+, LW(a-) sample was nonreactive. The patient's red blood cells (RBCs) typed as B, D-, LW(a-), K-, Fy(a-). Due to the age and clinical status of the child, 51Cr survival studies were not performed. One pediatric unit of D-, K-, Fy(a-) blood was transfused uneventfully; the expected increment of hemoglobin was achieved. Repeat testing 3 months later showed a weakly positive DAT, the patient's RBCs typed as LW(a+), and anti-LWa was detected only by a two-stage papain technique. These results suggest that the patient had a transient depression of LWa with a concurrent anti-LWa.
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PMID:An example of anti-LWa in a 10-month-old infant. 1594 14