Abstract:
:We propose that protein translocation across membranes is driven by biased random thermal motion. This "Brownian ratchet" mechanism depends on chemical asymmetries between the cis and trans sides of the membrane. Several mechanisms could contribute to rectifying the thermal motion of the protein, such as binding and dissociation of chaperonins to the translocating chain, chain coiling induced by pH and/or ionic gradients, glycosylation, and disulfide bond formation. This helps explain the robustness and promiscuity of these transport systems.
journal_name
Proc Natl Acad Sci U S Aauthors
Simon SM,Peskin CS,Oster GFdoi
10.1073/pnas.89.9.3770keywords:
subject
Has Abstractpub_date
1992-05-01 00:00:00pages
3770-4issue
9eissn
0027-8424issn
1091-6490journal_volume
89pub_type
杂志文章abstract::Wild-type p53 protein is a growth modulator whose inactivation has been found to be a key event in malignant transformation. Reconstitution of wild-type p53 in the p53-nonproducer, Abelson murine leukemia virus-transformed pre-B-cell line L12 gave rise to stably growing clones. Wild-type p53-producer derived cell line...
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.88.20.8982
更新日期:1991-10-15 00:00:00
abstract::We exploit the unusual genome organization of the ciliate cell to analyze the control of specific gene amplification during a nuclear differentiation process. Ciliates contain two types of nuclei within one cell, the macronucleus and the micronucleus; and after sexual reproduction a new macronucleus is formed from 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.1009284107
更新日期:2010-12-21 00:00:00
abstract::Diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein (or contre lumière) can be studied most reliably from above the earth's atmosphere with equipment flown in artificial satellites. We review the techniques used and some of the difficulties encountered ...
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.69.3.694
更新日期:1972-03-01 00:00:00
abstract::T cell activation and tolerance are regulated by costimulatory molecules. Although PD-1 serves as a crucial negative regulator of T cells, the function of its ligands, PDL1 and PDL2, is still controversial. In this study, we created a PDL2-deficient mouse to characterize its function in T cell activation and tolerance...
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.0601347103
更新日期:2006-08-01 00:00:00
abstract::The very low density lipoprotein (VLDL) receptor is a recently cloned member of the low density lipoprotein (LDL) receptor family that mediates the binding and uptake of VLDL when overexpressed in animal cells. Its sequence is 94% identical in humans and rabbits and 84% identical in humans and chickens, implying a con...
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.92.18.8453
更新日期:1995-08-29 00:00:00
abstract::The RuvB protein is induced in Escherichia coli as part of the SOS response to DNA damage. It is required for genetic recombination and the postreplication repair of DNA. In vitro, the RuvB protein promotes the branch migration of Holliday junctions and has a DNA helicase activity in reactions that require ATP hydroly...
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.91.16.7618
更新日期:1994-08-02 00:00:00
abstract::Ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (iGluRs) mediate the majority of excitatory synaptic transmission in the CNS and are essential for the induction and maintenance of long-term potentiation and long-term depression, two cellular models of learning and memory. We identi...
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.0708699104
更新日期:2007-11-13 00:00:00
abstract::Adult naive T cells, which are at rest in normal conditions, proliferate strongly when transferred to lymphopenic hosts. In neonates, the first mature thymocytes to migrate to the periphery reach a compartment devoid of preexisting T cells. We have extensively analyzed the proliferation rate and phenotype of periphera...
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.062621699
更新日期:2002-04-02 00:00:00
abstract::Multiple protein subcomplexes of the kinetochore cooperate as a cohesive molecular unit that forms load-bearing microtubule attachments that drive mitotic chromosome movements. There is intriguing evidence suggesting that central kinetochore components influence kinetochore-microtubule attachment, but the mechanism re...
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.1513882112
更新日期:2015-10-13 00:00:00
abstract::Subcortical structures play a critical role in brain function. However, options for assessing electrophysiological activity in these structures are limited. Electromagnetic fields generated by neuronal activity in subcortical structures can be recorded noninvasively, using magnetoencephalography (MEG) and electroencep...
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.1705414114
更新日期:2017-11-28 00:00:00
abstract::Mesp2 is a transcription factor that plays fundamental roles in somitogenesis, and its expression is strictly restricted to the anterior presomitic mesoderm just before segment border formation. The transcriptional on-off cycle is linked to the segmentation clock. In our current study, we show that a T-box transcripti...
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.0508238103
更新日期:2006-03-07 00:00:00
abstract::A Chinese hamster ovary cell (CHO) mutant (strain 58), defective in CDP-choline synthetase (cholinephosphate cytidylyltransferase; CTP:cholinephosphate cytidylyltransferase, EC 2.7.7.15), is temperature sensitive for growth and contains less than half of the normal amount of phosphatidylcholine under nonpermissive con...
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.79.6.1698
更新日期:1982-03-01 00:00:00
abstract::The engineering of structures across different length scales is central to the design of novel materials with controlled macroscopic properties. Herein, we introduce a unique class of self-assembling materials, which are built upon shape- and volume-persistent molecular nanoparticles and other structural motifs, such ...
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.1302606110
更新日期:2013-06-18 00:00:00
abstract::Interleukin 6 (IL-6) is a cytokine that acts on various cell types. Here we show that IL-6 mRNA is produced in vivo in two self-limiting physiologic angiogenic processes: (i) the formation of the vascular system accompanying development of ovarian follicles and (ii) the formation of a capillary network in the maternal...
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.87.8.3092
更新日期:1990-04-01 00:00:00
abstract::The extensive intratumor heterogeneity revealed by sequencing cancer genomes is an essential determinant of tumor progression, diagnosis, and treatment. What maintains heterogeneity remains an open question because competition within a tumor leads to a strong selection for the fittest subclone. Cancer cells also coope...
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.1414653112
更新日期:2015-02-10 00:00:00
abstract::Prolonged periods of extreme heat or drought in the first year after fire affect the resilience and diversity of fire-dependent ecosystems by inhibiting seed germination or increasing mortality of seedlings and resprouting individuals. This interaction between weather and fire is of growing concern as climate changes,...
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.1619014114
更新日期:2017-05-02 00:00:00
abstract::A fraction of the unintegrated viral DNA that appears early after infection of mouse cells by Moloney leukemia virus is infectious. The infectivity could be deomonstrated by an XC plaque assay of the cells exposed to DNA co-precipitated with calcium phosphate. The number of plaques deriving from closed-circular, super...
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.72.12.4910
更新日期:1975-12-01 00:00:00
abstract::Yawn contagion in humans has been proposed to be related to our capacity for empathy. It is presently unclear whether this capacity is uniquely human or shared with other primates, especially monkeys. Here, we show that in gelada baboons (Theropithecus gelada) yawning is contagious between individuals, especially thos...
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.0910891106
更新日期:2009-11-17 00:00:00
abstract::Human genetic studies have given evidence of familial, disease-causing mutations in the analogous amino acid residue shared by three related RNA binding proteins causative of three neurological diseases. Alteration of aspartic acid residue 290 of hnRNPA2 to valine is believed to predispose patients to multisystem prot...
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.1806174115
更新日期:2018-10-16 00:00:00
abstract::We find that the transcription of various ribosomal proteins can be differentially affected by polyamines and by changes in growth rates. Using strain MG1655 of Escherichia coli K-12 (F-, lambda-), we have determined the effects of polyamines and changes in growth rate on the transcription of several ribosomal genes 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.87.9.3464
更新日期:1990-05-01 00:00:00
abstract::We compared intron-exon structures in 1,560 human-mouse orthologs and 360 mouse-rat orthologs. The origin of differences in intron positions between species was inferred by comparison with an outgroup, Fugu for human-mouse and human for mouse-rat. Among 10,020 intron positions in the human-mouse comparison, we found u...
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.1232297100
更新日期:2003-06-10 00:00:00
abstract::Experimental lemurs either were infected orally with the agent of bovine spongiform encephalopathy (BSE) or were maintained as uninfected control animals. Immunohistochemical examination for proteinase-resistant protein (prion protein or PrP) was performed on tissues from two infected but still asymptomatic lemurs, ki...
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.96.7.4046
更新日期:1999-03-30 00:00:00
abstract::Which network structures favor the rapid spread of new ideas, behaviors, or technologies? This question has been studied extensively using epidemic models. Here we consider a complementary point of view and consider scenarios where the individuals' behavior is the result of a strategic choice among competing alternati...
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.1004098107
更新日期:2010-11-23 00:00:00
abstract::Results are reported showing that pituitary extracts stimulate growth of 3T3 cells, an established line of mouse fibroblast. Cells were cultured in medium containing an organic buffer (HEPES; N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid), which increases the serum requirement for cell growth. The pituitary grow...
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.70.9.2702
更新日期:1973-09-01 00:00:00
abstract::Fluorescence in situ hybridization (FISH) is a powerful tool for physical mapping in human and other mammalian species. However, application of the FISH technique has been limited in plant species, especially for mapping single- or low-copy DNA sequences, due to inconsistent signal production in plant chromosome prepa...
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.92.10.4487
更新日期:1995-05-09 00:00:00
abstract::Spin-polarized charge currents induce magnetic tunnel junction (MTJ) switching by virtue of spin-transfer torque (STT). Recently, by taking advantage of the spin-dependent thermoelectric properties of magnetic materials, novel means of generating spin currents from temperature gradients, and their associated thermal-s...
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.1507084112
更新日期:2015-05-26 00:00:00
abstract::The current epidemic of infections caused by antibiotic-resistant gram-positive bacteria requires the discovery of new drug targets and the development of new therapeutics. Lipoteichoic acid (LTA), a cell wall polymer of gram-positive bacteria, consists of 1,3-polyglycerol-phosphate linked to glycolipid. LTA synthase ...
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.1217337110
更新日期:2013-02-26 00:00:00
abstract::Control over structural transformations in supramolecular entities by external stimuli is critical for the development of adaptable and functional soft materials. Herein, we have designed and synthesized a dipyridyl donor containing a central Z-configured stiff-stilbene unit that self-assembles in the presence of two ...
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.1408620111
更新日期:2014-06-17 00:00:00
abstract::The fluorescence decay of the rare earth terbium when bound to the protein calmodulin changes from a simple exponential decay to a complex nonexponential decay as the temperature is lowered below 200 K. We have fit the observed decay curves by assuming that the terbium emission is a forced electric dipole transition 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.84.6.1541
更新日期:1987-03-01 00:00:00
abstract::A serpin was identified in normal mammary gland by differential cDNA sequencing. In situ hybridization has detected this serpin exclusively in the myoepithelial cells on the normal and noninvasive mammary epithelial side of the basement membrane and thus was named myoepithelium-derived serine proteinase inhibitor (MEP...
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.96.7.3700
更新日期:1999-03-30 00:00:00