Abstract:
:Protein phosphorylation is a ubiquitous and one of the most effective means of regulating protein activity. Receptor phosphorylation is a key event in signal transduction. The question, therefore, that arises is whether this modulatory mechanism might produce functional changes in a membrane receptor in the absence of its naturally occurring ligand. To examine this issue, single-channel properties of purified acetylcholine receptors (AChRs) from Torpedo californica reconstituted in lipid bilayers were studied in the absence of ACh in both unphosphorylated preparations and after in vitro phosphorylation by a purified catalytic subunit of cyclic AMP-dependent protein kinase (protein kinase A). Notably, the spontaneous open-channel probability of phosphorylated AChRs is significantly higher than that of unphosphorylated AChRs. Channel activation by protein kinase A is correlated with AChR phosphorylation and is abolished by alpha-bungarotoxin. Analysis of probability distributions of the open dwell times indicates that, similar to unphosphorylated AChR has two distinct open states, short- and long-lived. The frequency of occurrence of the long openings over the short and the magnitude of both time constants increase after phosphorylation, as they do with agonist concentration. Thus, phosphorylation of AChR gamma and delta subunits activates AChR channel opening in the absence of ligand binding. This result is compatible with the notion that protein phosphorylation may effectively act as an intracellular ligand with the phosphorylation sites envisioned as cytoplasmic ligand binding sites.
journal_name
Proc Natl Acad Sci U S Aauthors
Ferrer-Montiel AV,Montal MS,Díaz-Muñoz M,Montal Mdoi
10.1073/pnas.88.22.10213subject
Has Abstractpub_date
1991-11-15 00:00:00pages
10213-7issue
22eissn
0027-8424issn
1091-6490journal_volume
88pub_type
杂志文章abstract::Conjugation of drugs with antibodies to surface endothelial antigens is a potential strategy for drug delivery to endothelium. We studied antibodies to platelet-endothelial adhesion molecule 1 (PECAM-1, a stably expressed endothelial antigen) as carriers for vascular immunotargeting. Although 125I-labeled anti-PECAM b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.5.2379
更新日期:1999-03-02 00:00:00
abstract::High-entropy alloys are made from random mixtures of principal elements on simple lattices, stabilized by a high mixing entropy. The recently discovered body-centered cubic (BCC) Ta-Nb-Hf-Zr-Ti high-entropy alloy superconductor appears to display properties of both simple crystalline intermetallics and amorphous mater...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1615926113
更新日期:2016-11-15 00:00:00
abstract::It is well established that exposure to solar UVB (290-320 nm) gives rise to mutations in oncogenes and tumor suppressor genes that initiate the molecular cascade toward skin cancer. Although UVA (320-400 nm) has also been implicated in multistage photocarcinogenesis, its potential contribution to sunlight mutagenesis...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.6.2350
更新日期:1995-03-14 00:00:00
abstract::The aspartate receptor involved in chemotaxis is modified by methyl esterification at four distinct glutamate residues during the adaptive response of this receptor. To explain the high degree of specificity of this modification, it has been proposed that the methyltransferase recognizes the sequence Glu-Glu-Xaa-Xaa-A...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.18.6707
更新日期:1986-09-01 00:00:00
abstract::The present study investigated whether neural structures become less functionally differentiated and specialized with age. We studied ventral visual cortex, an area of the brain that responds selectively to visual categories (faces, places, and words) in young adults, and that shows little atrophy with age. Functional...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0405148101
更新日期:2004-08-31 00:00:00
abstract::Phosphocholine (PC) is an abundant primary form of organic phosphate that is transported in plant xylem sap. Addition of PC to the perfusate of compressed Pi-starved sycamore cells monitored by 31P NMR spectroscopy resulted in an accumulation of PC and all the other phosphate esters in the cytoplasmic compartment. Add...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.11.4280
更新日期:1990-06-01 00:00:00
abstract::The photoproduct of carbon monoxide myoglobin generated at 4 K and lower has a resonance Raman spectrum characteristic of a high-spin heme but in which the high-frequency core size-sensitive lines are at lower frequency than those in the deoxy preparation. Such differences are not detected in the photoproduct generate...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.5.1310
更新日期:1986-03-01 00:00:00
abstract::Under various conditions, specific genetic areas of the phage T4 DNA molecule are preferentially and repeatedly replicated, resulting in the amplification of these areas. These areas are found to lie in the vicinity of the known origins of DNA replication. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.77.9.5064
更新日期:1980-09-01 00:00:00
abstract::The chronometric redshift-distance relation z = tan 2(1/2rho), where rho is the distance in radians in the Einstein metric, is derived by an elementary geometric analysis comparable to that in traditional analysis of the expanding universe model. The differential dTt of Einstein time evolution Tt through time t, as ap...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.23.11114
更新日期:1993-12-01 00:00:00
abstract::Xenotropic and polytropic murine leukemia viruses (X-MLVs and P-MLVs) cross-interfere to various extents in non-mouse species and in wild Asian mice, suggesting that they might use a common receptor for infection. Consistent with this hypothesis, the susceptibility of some wild mice to X-MLVs has been mapped to the P-...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.3.927
更新日期:1999-02-02 00:00:00
abstract::Worldwide dissemination of antibiotic resistance in bacteria is facilitated by plasmids that encode postsegregational killing (PSK) systems. These produce a stable toxin (T) and a labile antitoxin (A) conditioning cell survival to plasmid maintenance, because only this ensures neutralization of toxicity. Shortage of a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1308241111
更新日期:2014-02-18 00:00:00
abstract::The retrotransposons that maintain telomeres in Drosophila melanogaster have unique features that are shared across all Drosophila species but are not found in other retrotransposons. Comparative analysis of these features provides insight into their importance for telomere maintenance in Drosophila. Gag proteins enco...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0702566104
更新日期:2007-05-15 00:00:00
abstract::Cyclooxygenase (COX)-2, a rate-limiting enzyme of prostaglandin (PG) production, is overexpressed in colorectal adenomas and adenocarcinomas, and its inhibition by nonsteroidal antiinflammatory drugs protects against colorectal cancer. Mechanisms of cancer promotion by COX-2 are not fully understood, but signaling thr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1533221100
更新日期:2003-07-22 00:00:00
abstract::IL-27-induced type 1 regulatory T (Tr1) cells suppress autoimmunity by producing IL-10. Signal transducer and activator of transcription (STAT) 1 and STAT3 have been described as key transcription factors that promote IL-10 secretion from Tr1 cells induced by IL-27. However, the molecular pathways for negatively regul...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1211776110
更新日期:2013-05-07 00:00:00
abstract::Chromatin condensation plays an important role in the regulation of gene expression. Recently, it was shown that the transcriptional activation of Hoxd genes during vertebrate digit development involves modifications in 3D interactions within and around the HoxD gene cluster. This reorganization follows a global trans...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1517972112
更新日期:2015-11-10 00:00:00
abstract::The recognition of carrier proteins by multiple catalytic partners occurs in every cycle of chain elongation in the biosynthesis of fatty acids and of the pharmacologically important polyketide and nonribosomal peptide natural products. To dissect the features of carrier proteins that determine specific recognition at...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0705122104
更新日期:2007-07-10 00:00:00
abstract::Temporal patterning of biological variables, in the form of oscillations and rhythms on many time scales, is ubiquitous. Altering the temporal pattern of an input variable greatly affects the output of many biological processes. We develop here a conceptual framework for a quantitative understanding of such pattern de...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.19.10444
更新日期:1997-09-16 00:00:00
abstract::Infant maltreatment increases vulnerability to physical and mental disorders, yet specific mechanisms embedded within this complex infant experience that induce this vulnerability remain elusive. To define critical features of maltreatment-induced vulnerability, rat pups were reared from postnatal day 8 (PN8) with a m...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1907170116
更新日期:2019-11-05 00:00:00
abstract::We studied the abundance and structure of globin mRNAs present in K562 cells both before and after induction of hemoglobin synthesis by hemin. In vitro translation of poly(A)+ RNA from K562 cells generated protein products corresponding to alpha, A gamma-, G gamma-, epsilon-, and zeta-globin mRNAs. Individual globin m...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.18.5515
更新日期:1983-09-01 00:00:00
abstract::Cucumber mosaic virus (CMV) and tomato aspermy virus (TAV) belong to the Cucumovirus genus. They have a tripartite genome consisting of single-stranded RNAs, designated 1, 2, and 3. Previous studies have shown that viable pseudorecombinants could be created in vitro by reciprocal exchanges between CMV and TAV RNA 3, b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.18.10487
更新日期:1998-09-01 00:00:00
abstract::Drosophila Numb is a membrane associated protein of 557 amino acids (aa) that localizes asymmetrically into a cortical crescent in mitotic neural precursor cells and segregates into one of the daughter cells, where it is required for correct cell fate specification. We demonstrate here that asymmetric localization but...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.24.13005
更新日期:1997-11-25 00:00:00
abstract::It is shown that, under certain standard assumptions, such as extended Riemann hypotheses, the scattering matrix varphi(s) for generic Gamma = SL(2, R) is unexpectedly of order 2. This leads to the conjecture that the generic cofinite Gamma has very few Maass cusp forms. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.11.3533
更新日期:1985-06-01 00:00:00
abstract::Engaging mammalian Toll-like receptors (TLRs) activate both the NF-kappaB and mitogen-activated protein kinase signaling pathways. Here we establish that mitogen-activated protein 3 kinase Tpl2, levels of which are markedly reduced in nfkb1(-/-) cells, is required for extracellular signal-regulated kinase (ERK) activa...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0511113103
更新日期:2006-02-28 00:00:00
abstract::Using a high-resolution isoelectric focusing system, we have been able to separate the products of the individual "nonallelic+ mouse hemoglobin alpha-chain genes. The hemoglobins of mice of inbred strains that make two structurally different, but electrophoretically identical, alpha chains resolve into two bands on is...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.2.867
更新日期:1979-02-01 00:00:00
abstract::In addition to their well-recognized hepatotropism, all hepatitis B viruses (HBVs) display marked species specificity, growing poorly or not at all in species other than those closely related to their natural hosts. We have examined the molecular basis for this narrow host range, using duck HBV (DHBV) and heron HBV (H...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.14.6259
更新日期:1995-07-03 00:00:00
abstract::Cell fusion was induced by brain extracts containing the scrapie virus and the virus of Creutzfeldt-Jakob disease. The assay involved quantitation of colony-forming ability in a double selection system, strandardized against fusion induced by Sendai virus. Correlation between the logarithm of virus dilution and the hy...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.75.6.2969
更新日期:1978-06-01 00:00:00
abstract::The protease encoded by the human immunodeficiency virus (HIV) processes the viral gag and gag-pol protein precursor by posttranslational cleavage. In this study we have demonstrated by site-specific mutagenesis (Asp----Thr) and by pepstatin A inhibition that the recombinant HIV protease is an aspartic-type protease. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.18.6612
更新日期:1988-09-01 00:00:00
abstract::Exposure to green space has been associated with better physical and mental health. Although this exposure could also influence cognitive development in children, available epidemiological evidence on such an impact is scarce. This study aimed to assess the association between exposure to green space and measures of c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1503402112
更新日期:2015-06-30 00:00:00
abstract::The structure of the non-self-complementary DNA heptamer d(CGACGAC) at low pH has been determined by the quantitative NMR refinement procedure designated SPEDREF (SPEctral-Driven REFinement). Acid-base titration of the molecule indicated a prominent n = 2 pKa near 6.8. In the pH range up to 6.0, the heptamer forms a r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.11.5224
更新日期:1993-06-01 00:00:00
abstract::Protein Hal is a human gamma4 heavy-chain disease protein whose molecular weight is reduced from 55,000 to 25,000 in 6 M guanidine due to the lack of disulfide bonds between heavy chains. Studies of aminoacid sequence indicate that it contains a gap of about 240 residues, starting 10 residues from the N-terminal end a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.70.4.1073
更新日期:1973-04-01 00:00:00