“ATP-binding cassette transporter A1 (ABCA1) mediates apolipoprotein-dependent cholesterol release from cellular membranes. Recent studies using ABCA1 knockout mice have demonstrated that ABCAI affects amyloid-beta peptide (A beta) levels in the brain and the production of senile plaque. Cerebral A beta(1-40) was eliminated from the brain to the circulating blood via the blood-brain barrier (BBB), CYT387 in vitro which expresses ABCA1. Therefore, in the present study, we examined whether ABCAI affects the brain-to-blood efflux transport of human A beta(1-40)(hA beta(1-40)) at the BBB. The apparent uptake of [I-125]hA beta(1-40)
into ABCA1-expressing HEK293 cells was not significantly different
from that into parental HEK293 cells. In addition, the apparent uptake was not significantly affected even in the presence of apolipoprotein A-I as a cholesterol release acceptor. Moreover, [I-125]hA beta(1-40) elimination from mouse brain across the BBB was not significantly different between ABCA1-deficient and wild-type mice 60 min after its administration into the cerebrum. These results suggest that ABCAI does not directly transport hA beta(1-40) and a deficiency of ABCAI does not attenuate the brain-to-blood PRIMA-1MET order efflux transport of hA beta(1-40) across the BBB. (C) 2007 Elsevier Ltd. All rights reserved.”
“p300 and CREB-binding protein (CBP) act as multifunctional regulators of p53 via acetylase and polyubiquitin ligase (E4) activities. Prior work in vitro has shown that the N-terminal 595 aa of p300 encode both generic ubiquitin ligase (E3) and p53-directed E4 functions. Analysis of p300 or CBP-deficient cells revealed that both coactivators were required for endogenous p53 polyubiquitination and the normally rapid turnover of p53 in unstressed cells. Unexpectedly, p300/CBP ubiquitin ligase activities were absent in nuclear extracts and exclusively cytoplasmic. Consistent with the cytoplasmic localization of its E3/E4 activity, CBP deficiency specifically stabilized cytoplasmic, but not nuclear p53. The N-terminal
616 aa of CBP, which includes the conserved Zn(2+)-binding C/H1-TAZ1 domain, was the minimal domain sufficient to destabilize Selleck Selisistat p53 in vivo, and it included within an intrinsic E3 autoubiquitination activity and, in a two-step E4 assay, exhibited robust E4 activity for p53. Cytoplasmic compartmentalization of p300/CBP’s ubiquitination function reconciles seemingly opposed functions and explains how a futile cycle is avoided-cytoplasmic p300/CBP E4 activities ubiquitinate and destabilize p53, while physically separate nuclear p300/CBP activities, such as p53 acetylation, activate p53.”
“Use of dietary supplements in the U. S. has increased steadily over the last 25 years. While misformulation is uncommon, the consequences can be serious.