BACKGROUND & AIMS: The mammalian transcription factor LSF (CP2/LBP-1c) binds cellular promoters modulated by cell growth signals. We demonstrate here that LSF-DNA-binding activity is strikingly regulated by induction of cell growth in human peripheral T lymphocytes. Within 15 min of mitogenic stimulation of these cells, the level of LSF-DNA-binding activity increased by a factor of five. The level of LSF protein in the nucleus remained constant throughout this interval. However, a rapid decrease in the electrophoretic mobility of LSF, attributable to phosphorylation, correlated with the increase in DNA-binding activity. pp44 (ERK1) phosphorylated LSF in vitro on the same residue that was phosphorylated in vivo, specifically at amino acid position 291, as indicated by mutant analysis. As direct verification of the causal relationship between phosphorylation and DNA-binding activity, treatment in vitro of LSF with phosphatase both increased the electrophoretic mobility of the protein and decreased LSF-DNA-binding activity. This modulation of LSF-DNA-binding activity as T cells progress from a resting to a replicating state reveals that LSF activity is regulated during cell growth and suggests that LSF regulates growth-responsive promoters.

背景与目标： 哺乳动物转录因子LSF（CP2 / LBP-1c）结合受细胞生长信号调节的细胞启动子。我们在这里证明，LSF-DNA结合活性是由人类外周血T淋巴细胞的细胞生长诱导来显着调节的。在这些细胞的促有丝分裂刺激的15分钟内，LSF-DNA结合活性的水平提高了五倍。在整个间隔期间，核中LSF蛋白的水平保持恒定。但是，可归因于磷酸化的LSF电泳迁移率的快速下降与DNA结合活性的增加有关。突变分析表明，pp44（ERK1）在体外磷酸化的同一残基上，特别是在氨基酸位置291处磷酸化LSF。作为磷酸化与DNA结合活性之间因果关系的直接验证，体外用磷酸酶处理LSF既增加了蛋白质的电泳迁移率，又降低了LSF-DNA结合活性。当T细胞从静止状态发展到复制状态时，对LSF-DNA结合活性的这种调节揭示了LSF活性在细胞生长过程中受到调节，并暗示LSF调节生长响应性启动子。

BACKGROUND & AIMS: Modelling and calculations are presented as a first step towards mechanistic interpretation and prediction of radiation effects based on the spectrum of initial DNA damage produced by low energy electrons (100 eV-4.5 keV) that can be compared with experimental information. Relative yields of single and clustered strand breaks are presented in terms of complexity and source of damage, either by direct energy deposition or by reaction of OH radicals, and dependence on the activation probability of OH radicals and the amount of energy required to give a single strand break (ssb). Data show that the majority of interactions in DNA do not lead to damage in the form of strand breaks and when they do occur, they are most frequently simple ssb. However, for double-strand breaks (dsb), a high proportion (approximately 30%) are of more complex forms, even without considering additional complexity from base damage. The greater contribution is from direct interactions in the DNA but reactions of OH radicals add substantially to this, both in terms of the total number of breaks and in increasing the complexity within a cluster. It has been shown that the lengths of damaged segments of DNA from individual electron tracks tend to be short, indicating that consequent deletion length (simply by loss of a fragment between nearby dsb) would be short, very seldom exceeding a few tens of base pairs.

背景与目标： 建模和计算是迈向机理解释和辐射效应预测的第一步，该过程基于低能电子（100 eV-4.5 keV）产生的初始DNA损伤的光谱，可以与实验信息进行比较。单链和簇状链断裂的相对产率通过复杂性和破坏源（通过直接能量沉积或OH自由基的反应）以及OH自由基的活化概率和产生单原子所需的能量的数量来表示。断链（ssb）。数据表明，DNA中的大多数相互作用都不会以链断裂的形式导致损伤，并且当它们发生时，它们通常是简单的单链断裂。但是，对于双链断裂（dsb），即使不考虑基础损伤带来的额外复杂性，也有较高比例（约30％）具有更复杂的形式。更大的贡献来自于DNA中的直接相互作用，但是OH自由基的反应在断裂总数和增加簇内复杂性方面都大大增加了这一点。已经显示，来自单个电子迹线的DNA的受损片段的长度趋于较短，表明随后的缺失长度（仅由于附近dsb之间的片段的丢失）将较短，很少很少超过几十个碱基对。 。

BACKGROUND & AIMS: :The pathogenicity of the plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion system which is encoded by the 23-kb hrp (hypersensitive response and pathogenicity) gene cluster. Expression of the hrp operons is strongly induced in planta and in a special minimal medium and depends on two regulatory proteins, HrpG and HrpX. In this study, DNA affinity enrichment was used to demonstrate that the AraC-type transcriptional activator HrpX binds to a conserved cis-regulatory element, the plant-inducible promoter (PIP) box (TTCGC-N(15)-TTCGC), present in the promoter regions of four hrp operons. No binding of HrpX was observed when DNA fragments lacking a PIP box were used. HrpX also bound to a DNA fragment containing an imperfect PIP box (TTCGC-N(8)-TTCGT). Dinucleotide replacements in each half-site of the PIP box strongly decreased binding of HrpX, while simultaneous dinucleotide replacements in both half-sites completely abolished binding. Based on the complete genome sequence of Xanthomonas campestris pv. vesicatoria, putative plant-inducible promoters consisting of a PIP box and a -10 promoter motif were identified in the promoter regions of almost all HrpX-activated genes. Bioinformatic analyses and reverse transcription-PCR experiments revealed novel HrpX-dependent genes, among them a NUDIX hydrolase gene and several genes with a predicted role in the degradation of the plant cell wall. We conclude that HrpX is the most downstream component of the hrp regulatory cascade, which is proposed to directly activate most genes of the hrpX regulon via binding to corresponding PIP boxes.

背景与目标： ：植物致病性细菌Xanthomonas campestris pv的致病性。 vesicatoria依赖于由23-kb hrp（过敏反应和致病性）基因簇编码的III型分泌系统。 hrp操纵子的表达在植物和特殊的基本培养基中强烈诱导，并依赖于两种调节蛋白HrpG和HrpX。在这项研究中，DNA亲和力富集用于证明AraC型转录激活因子HrpX与保守的顺式调控元件，即植物诱导型启动子（PIP）框（TTCGC-N（15）-TTCGC）结合，四个hrp操纵子的启动子区域。当使用缺少PIP盒的DNA片段时，未观察到HrpX的结合。 HrpX还绑定到包含不完整的PIP盒（TTCGC-N（8）-TTCGT）的DNA片段。 PIP盒每个半位中的二核苷酸替换强烈降低了HrpX的结合，而两个半位中同时进行的二核苷酸替换则完全消除了结合。基于Xanthomonas campestris pv的完整基因组序列。在几乎所有的HrpX激活基因的启动子区域中，鉴定出了由vesptoria组成的假定的植物诱导型启动子，该启动子由PIP框和-10个启动子组成。生物信息学分析和逆转录-PCR实验揭示了新的HrpX依赖性基因，其中包括NUDIX水解酶基因和几个在植物细胞壁降解中具有预测作用的基因。我们得出的结论是，HrpX是hrp调节级联的最下游组件，建议通过与相应的PIP盒结合直接激活hrpX regulon的大多数基因。

BACKGROUND & AIMS: We studied changes in glutamate receptors, expression of immediate early genes, and AP-1 DNA binding activity in the brains of phenobarbital (PB)-dependent and -withdrawn rats to investigate the possible involvement of activation of glutamate receptors in PB withdrawal syndrome. PB-dependent rats were prepared by feeding drug-admixed food for 5 weeks. Autoradiographic analysis showed that binding of [3H(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imin e (MK-801), an antagonist of N-methyl-D-aspartic acid (NMDA) receptors, increased significantly in the cerebral cortices of PB-dependent and 24-h-withdrawn rats. However, [3H]MK-801 binding in the hippocampus and [3H]6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and [3H]kainic acid binding in the hippocampus and cerebral cortex were essentially unchanged in both groups. PB withdrawal seizures were followed by increased expression of c-fos mRNA in the hippocampus and cerebral cortex and of c-jun mRNA in the cerebral cortex. The induction of c-fos and c-jun mRNA was suppressed by administration of MK-801. Furthermore, PB withdrawal enhanced AP-1 DNA binding activity in the brain. The present findings suggest functional enhancement of glutamatergic neurotransmission during the development of PB withdrawal syndrome.

背景与目标： 我们研究了苯巴比妥（PB）依赖和戒断大鼠大脑中谷氨酸受体的变化，立即早期基因的表达以及AP-1 DNA结合活性，以研究谷氨酸受体激活在PB戒断综合征中的可能。通过喂食药物混合的食物5周来制备PB依赖的大鼠。放射自显影分析表明，[3H（）-5-甲基-10,11-二氢-5H-二苯并[a，d]环庚烯-5,10-亚胺e（MK-801）与N-甲基- D-天冬氨酸（NMDA）受体，在PB依赖和24小时戒断大鼠的大脑皮层中显着增加。然而，在海马中的[3H] MK-801结合以及在海马和大脑皮层中的[3H] 6-氰基-7-硝基喹喔啉-2,3-二酮（CNQX）和[3H]海藻酸结合基本上没有变化。组。 PB抽搐发作后，海马和大脑皮层中c-fos mRNA的表达增加，大脑皮层中c-jun mRNA的表达增加。通过施用MK-801抑制了c-fos和c-jun mRNA的诱导。此外，PB撤离可增强大脑中AP-1 DNA的结合活性。目前的发现表明，在PB戒断综合征的发展过程中，谷氨酸能神经传递的功能增强。

BACKGROUND & AIMS: Tyrosine phosphorylation of the nicotinic acetylcholine receptor (AChR) is associated with an altered rate of receptor desensitization and also may play a role in agrin-induced receptor clustering. We have demonstrated a previously unsuspected interaction between Torpedo AChR and the adaptor protein Grb2. The binding is mediated by the Src homology 2 (SH2) domain of Grb2 and the tyrosine-phosphorylated delta subunit of the AChR. Dephosphorylation of the delta subunit abolishes Grb2 binding. A cytoplasmic domain of the delta subunit contains a binding motif (pYXNX) for the SH2 domain of Grb2. Indeed, a phosphopeptide corresponding to this region of the delta subunit binds to Grb2 SH2 fusion proteins with relatively high affinity, whereas a peptide lacking phosphorylation on tyrosine exhibits no binding. Grb2 is colocalized with the AChR on the innervated face of Torpedo electrocytes. Furthermore, Grb2 specifically copurifies with AChR solubilized from postsynaptic membranes. These data suggest a novel role for tyrosine phosphorylation of the AChR in the initiation of a Grb2-mediated signaling cascade at the postsynaptic membrane.

背景与目标： 烟碱样乙酰胆碱受体（AChR）的酪氨酸磷酸化与受体脱敏率的改变有关，也可能在凝集素诱导的受体簇中起作用。我们已经证明了鱼雷AChR和衔接蛋白Grb2之间以前没有想到的相互作用。结合是由Grb2的Src同源2（SH2）域和AChR的酪氨酸磷酸化的δ亚基介导的。 δ亚基的去磷酸化消除了Grb2结合。 δ亚基的胞质结构域包含Grb2的SH2结构域的结合基序（pYXNX）。实际上，对应于δ亚基的该区域的磷酸肽以相对高的亲和力与Grb2 SH2融合蛋白结合，而在酪氨酸上缺乏磷酸化的肽没有结合。 Grb2与AChR在鱼雷电池的神经支配面上共定位。此外，Grb2与从突触后膜溶解的AChR特异性共纯化。这些数据表明，AChR的酪氨酸磷酸化在突触后膜的Grb2介导的信号级联反应的起始中起着新的作用。

BACKGROUND & AIMS: The GATA family of vertebrate DNA binding regulatory proteins are expressed in diverse tissues and at different times of development. However, the DNA binding regions of these proteins possess considerable homology and recognize a rather similar range of DNA sequence motifs. DNA binding is mediated through two domains, each containing a zinc finger. Previous results have led to the conclusion that although in some cases the N-terminal finger can contribute to specificity and strength of binding, it does not bind independently, whereas the C-terminal finger is both necessary and sufficient for binding. Here we show that although this is true for the N-terminal finger of GATA-1, those of GATA-2 and GATA-3 are capable of strong independent binding with a preference for the motif GATC. Binding requires the presence of two basic regions located on either side of the N-terminal finger. The absence of one of these near the GATA-1 N-terminal finger probably accounts for its inability to bind. The combination of a single finger and two basic regions is a new variant of a motif that has been previously found in the binding domains of other finger proteins. Our results suggest that the DNA binding properties of the N-terminal finger may help distinguish GATA-2 and GATA-3 from GATA-1 and the other GATA family members in their selective regulatory roles in vivo.

背景与目标： GATA家族的脊椎动物DNA结合调节蛋白在不同的组织中以及在不同的发育时期表达。但是，这些蛋白质的DNA结合区具有相当的同源性，可以识别相当相似范围的DNA序列基序。 DNA结合是通过两个结构域介导的，每个结构域都包含一个锌指。先前的结果得出的结论是，尽管在某些情况下N末端指可以有助于结合的特异性和强度，但它不能独立地结合，而C末端指对于结合既是必需的又是足够的。在这里，我们表明，尽管对于GATA-1的N端手指来说确实如此，但GATA-2和GATA-3的手指却能够强烈独立地结合，并优先选择基序GATC。绑定需要在N末端指状体的两侧都存在两个基本区域。在GATA-1 N端手指附近缺少这些手指之一可能是其无法结合的原因。单个手指和两个基本区域的组合是一个基序的新变体，该变体先前已在其他手指蛋白的结合域中发现。我们的结果表明，N末端手指的DNA结合特性可能有助于区分GATA-2和GATA-3与GATA-1和其他GATA家族成员在体内的选择性调节作用。

BACKGROUND & AIMS: :Related outer membrane proteins, termed secretins, participate in the secretion of macromolecules across the outer membrane of many Gram-negative bacteria. In the pullulanase-secretion system, PulS, an outer membrane-associated lipoprotein, is required both for the integrity and the proper outer membrane localization of the PulD secretin. Here we show that the PulS-binding site is located within the C-terminal 65 residues of PulD. Addition of this domain to the filamentous phage secretin, pIV, or to the unrelated maltose-binding protein rendered both proteins dependent on PulS for stability. A chimeric protein composed of bacteriophage f1 pIV and the C-terminal domain of PuID required properly localized PulS to support phage assembly. An in vivo complex formed between the pIV-PulD65 chimera and PulS was detected by co-immunoprecipitation and by affinity chromatography.

背景与目标： ：相关的外膜蛋白，称为促胰液素，参与许多革兰氏阴性细菌的外膜大分子的分泌。在支链淀粉酶分泌系统中，PulS是一种与外膜相关的脂蛋白，是PulD促胰液素的完整性和正确的外膜定位所必需的。在这里，我们显示PulS结合位点位于PulD的C末端65个残基内。此结构域添加到丝状噬菌体分泌蛋白，pIV或无关的麦芽糖结合蛋白上，使得这两种蛋白都依赖于PulS来保持稳定性。由噬菌体f1 pIV和PuID的C末端结构域组成的嵌合蛋白需要正确定位PulS以支持噬菌体装配。通过共免疫沉淀法和亲和色谱法检测到了pIV-PulD65嵌合体和PulS之间形成的体内复合物。

BACKGROUND & AIMS: :Gu/RNA helicase II (Gu/RH-II) is the first reported mammalian nucleolar RNA helicase that is a member of the D-E-A-D (Asp-Glu-Ala-Asp) box family of proteins. It has an ATP-dependent RNA unwinding (helicase) activity and a separate RNA folding activity (introduction of intramolecular secondary structure into single-stranded RNA). To determine which proteins may bind to Gu/RH-II, a yeast two-hybrid system was used. A cDNA which encoded a protein, called Gu/RH-II binding protein or GBP, was isolated and sequenced. The GBP protein is localized to the nucleus in speckled or diffuse nucleoplasmic patterns. The GBP mRNA level is highest in testis, 9- to 49-fold greater than other tissues. When GBP interacts with Gu/RH-II, proteolytic cleavage of Gu/RH-II occurs; the amino-terminal portion of Gu/RH-II is critical for this proteolysis.

背景与目标： ：Gu / RNA解旋酶II（Gu / RH-II）是第一个报道的哺乳动物核仁RNA解旋酶，它是D-E-A-D（Asp-Glu-Ala-Asp）盒蛋白家族的成员。它具有ATP依赖的RNA解旋（解旋酶）活性和单独的RNA折叠活性（将分子内二级结构引入单链RNA）。为了确定哪些蛋白质可以与Gu / RH-II结合，使用了酵母双杂交系统。分离并测序了编码称为Gu / RH-II结合蛋白或GBP的蛋白质的cDNA。 GBP蛋白以斑点或弥散的核质模式定位于细胞核。 GBP mRNA水平在睾丸中最高，比其他组织高9到49倍。当GBP与Gu / RH-II相互作用时，会发生Gu / RH-II的蛋白水解切割。 Gu / RH-II的氨基末端部分对于这种蛋白水解至关重要。

BACKGROUND & AIMS: :Human immunodeficiency virus (HIV) binds to cells via an interaction between CD4 and the virus envelope glycoprotein, gp120. Previous studies have localized the high affinity binding site for gp120 to the first domain of CD4, and monoclonal antibodies (mAbs) reactive with this region compete with gp120 binding and thereby block virus infectivity and syncytium formation. Despite a detailed understanding of the binding of gp120 to CD4, little is known of subsequent events leading to membrane fusion and virus entry. We describe two new mAbs reactive with the third domain of CD4 that inhibit steps subsequent to virus binding critical for HIV infectivity and cell fusion. Binding of recombinant gp120 or virus to CD4 is not inhibited by these antibodies, whereas infection and syncytium formation by a number of HIV isolates are blocked. These findings demonstrate that in addition to virus binding, CD4 may have an active role in membrane fusion.

背景与目标： 人类免疫缺陷病毒（HIV）通过CD4和病毒包膜糖蛋白gp120之间的相互作用与细胞结合。先前的研究已经将gp120的高亲和力结合位点定位在CD4的第一个域，并且与该区域反应的单克隆抗体（mAb）与gp120结合竞争，从而阻断了病毒的感染性和合胞体的形成。尽管对gp120与CD4的结合有详细的了解，但对导致膜融合和病毒进入的后续事件知之甚少。我们描述了与CD4的第三个域具有反应性的两个新的单克隆抗体，可抑制继病毒结合后对HIV感染性和细胞融合至关重要的步骤。重组gp120或病毒与CD4的结合不受这些抗体的抑制，而许多HIV分离株的感染和合胞体形成却被阻止。这些发现表明，除病毒结合外，CD4可能在膜融合中发挥积极作用。

BACKGROUND & AIMS: :The regulation of ion channels and transporters by anionic phospholipids is currently very topical. G protein-gated K(+) channels from the Kir3.0 family are involved in slowing the heart rate, generating late inhibitory postsynaptic potentials and controlling hormone release from neuroendocrine cells. There is considerable functional precedent for the control of these channels by phosphatidylinositol 4,5-bisphosphate. In this study, we used a biochemical assay to investigate the lipid binding properties of Kir3.0 channel domains. We reveal a differential binding affinity to a range of phosphoinositides between the C termini of the Kir3.0 isoforms. Furthermore, the N terminus in addition to the C terminus of Kir3.4 is necessary to observe binding and is decreased by the mutations R72A, K195A and R196A but not K194A. Protein kinase C phosphorylation of the Kir3.1 C-terminal fusion protein decreases anionic phospholipid binding. The differential binding affinity has functional consequences as the inhibition of homomeric Kir3.1, occurring after M3 receptor activation, recovers over minutes while homomeric Kir3.2 does not.

背景与目标： ：阴离子磷脂对离子通道和转运蛋白的调节目前非常热门。 Kir3.0家族的G蛋白门控的K（）通道参与减慢心率，产生晚期抑制的突触后电位并控制神经内分泌细胞的激素释放。磷脂酰肌醇4，5-双磷酸酯对这些通道的控制有相当大的功能先例。在这项研究中，我们使用生化分析来研究Kir3.0通道域的脂质结合特性。我们揭示了对Kir3.0亚型的C末端之间的一系列磷酸肌醇的不同结合亲和力。此外，除了观察Kir3.4的C末端外，N末端对于观察结合也是必需的，并且由于突变R72A，K195A和R196A而不是K194A而降低。 Kir3.1 C端融合蛋白的蛋白激酶C磷酸化减少了阴离子磷脂的结合。差异结合亲和力具有功能性后果，因为抑制M3受体激活后发生的同源Kir3.1抑制会在数分钟内恢复，而同源Kir3.2不会恢复。

BACKGROUND & AIMS: We have used 600 MHz 1H NMR spectroscopy data to determine the solution structure of a 31-residue domain of a murine class II major histocompatibility (MHC) protein. This domain, I-Ab(beta)-(60-90), binds to the superantigen staphylococcal enterotoxin A. Distance geometry and dynamical simulated annealing calculations were performed using NOESY- and COSY-deduced constraints. I-Ab(beta)-(60-90), which is mostly alpha-helical, is more similar to the corresponding region of the class II MHC protein HLA-DR1 than to the class I MHC protein HLA-A2. Arg-72 and Arg-80 lie on the same side of the helix and face away from the antigenic peptide binding groove. His-81, implicated in both superantigen and peptide binding, is located midway between the surface defined by Arg-72/Arg-80 and residues that define the inside of the peptide binding groove, allowing for its participation in both types of binding.

背景与目标： 我们已经使用600 MHz 1H NMR光谱数据确定了鼠类II类主要组织相容性（MHC）蛋白的31个残基域的溶液结构。该域I-Abβ-（60-90）与超抗原葡萄球菌肠毒素A结合。使用NOESY和COSY推导的约束条件进行距离几何结构和动态模拟退火计算。 I-Abβ-（60-90）主要是α-螺旋，与II类MHC蛋白HLA-DR1的相应区域相比，与I类MHC蛋白HLA-A2的对应区域更为相似。 Arg-72和Arg-80位于螺旋的同一侧，背对抗原肽结合槽。 His-81涉及超抗原和肽的结合，位于Arg-72 / Arg-80定义的表面与定义肽结合槽内部的残基之间的中间位置，允许其参与两种结合类型。 br>

BACKGROUND & AIMS: :In monocytes, the fimbriae of the oral pathogen Porphyromonas gingivalis activate cross talk signaling from Toll-like receptor 2 (TLR2) to the beta2 integrin CD11b/CD18, leading to the induction of the high-affinity state of the latter receptor. CD14 plays an important role in this "inside-out" proadhesive pathway by binding fimbriae and facilitating the activation of TLR2 and phosphatidylinositol 3-kinase signaling. In its high-affinity state, CD11b/CD18 mediates monocyte adhesion to endothelial cells and transmigration to sites of infection. We have now shown that P. gingivalis fimbriae function as both an activator and a ligand of CD11b/CD18; thus, fimbriae proactively promote their own binding to monocytes. Indeed, treatments that interfered with fimbria-induced activation of CD11b/CD18 (i.e., blockade of CD14, TLR2, or phosphatidylinositol 3-kinase signaling) also suppressed the cell binding activity of fimbriae, which was largely inducible and CD11b/CD18 dependent. Development of a recombinant inside-out signaling system in Chinese hamster ovary cells confirmed the ability of fimbriae to activate CD14/TLR2 signaling and induce their own CD11b/CD18-dependent binding. Induction of this proadhesive pathway by P. gingivalis fimbriae appeared to take place in lipid rafts. Indeed, methyl-beta-cyclodextrin, a cholesterol-sequestering agent that disrupts lipid raft organization, was found to inhibit the fimbria-induced assembly of CD14/TLR2 signaling complexes and the activation of the high-affinity state of CD11b/CD18. Experiments using macrophages from mice deficient in various pattern recognition receptors indicated that the receptors involved in the inside-out proadhesive pathway (CD14, TLR2, and CD11b/CD18) are important for mediating P. gingivalis internalization within macrophages. It therefore appears that P. gingivalis proactively modulates beta2 integrin adhesive activity for intracellular uptake.

背景与目标： ：在单核细胞中，口腔病原体牙龈卟啉单胞菌的菌毛激活了从Toll样受体2（TLR2）到β2整联蛋白CD11b / CD18的串扰信号，从而导致了后者受体的高亲和力状态的诱导。 CD14通过结合菌毛并促进TLR2和磷脂酰肌醇3激酶信号的激活，在此“由内而外”的前粘附途径中起重要作用。在其高亲和力状态下，CD11b / CD18介导单核细胞与内皮细胞的粘附并转移到感染部位。现在我们已经显示，牙龈卟啉单胞菌菌毛既是CD11b / CD18的激活剂又是其配体；因此，菌毛主动地促进其自身与单核细胞的结合。实际上，干扰菌毛诱导的CD11b / CD18活化（即阻断CD14，TLR2或磷脂酰肌醇3-激酶信号传导）的治疗也抑制了菌毛的细胞结合活性，其在很大程度上是诱导性的并且是CD11b / CD18依赖性的。中国仓鼠卵巢细胞中一种由内而外的重组信号系统的开发证实了菌毛具有激活CD14 / TLR2信号并诱导其自身CD11b / CD18依赖性结合的能力。齿龈假单胞菌对这种前粘性途径的诱导似乎发生在脂质筏中。实际上，已发现甲基-β-环糊精（一种可破坏脂质筏组织的胆固醇替代剂）可抑制菌毛诱导的CD14 / TLR2信号复合物的装配以及CD11b / CD18的高亲和力状态的激活。使用来自缺乏各种模式识别受体的小鼠的巨噬细胞进行的实验表明，参与由内而外的前粘附途径的受体（CD14，TLR2和CD11b / CD18）对于介导巨噬细胞内牙龈卟啉单胞菌的内化作用很重要。因此，似乎牙龈卟啉单胞菌主动地调节β2整联蛋白的粘附活性以用于细胞内摄取。

BACKGROUND & AIMS: Mucin-type glycoproteins carrying sialylLeA antigens (SL-GP) were isolated from the ascites fluid of a patient with colorectal cancer. SL-GP bound to E-selectin on endothelial cells in Ca2+- and sialylLeA antigen-dependent manners. To examine the metabolic change in E-selectin caused by ligation, endothelial cells were labeled with 32P-phosphate or 35S-Met and 35S-Cys. Phosphorylation at one or more serine residues of E-selectin was elevated by ligation with SL-GP but not with sialylLeA hexasaccharide. Pulse-labeling of E-selectin with 35S-Met and 35S-Cys in the presence of SL-GP indicated that the degradation of E-selectin was accelerated by SL-GP ligation, but labeling after pre-ligation with SL-GP revealed an increase in the synthesis of E-selectin. The synthesis may reflect compensation for the E-selectin degraded on pre-ligation. These results indicate that the overall metabolism of E-selectin was enhanced by the ligation of SL-GP, with degradation and synthesis being apparently balanced.

背景与目标： 从患有结肠直肠癌的患者的腹水中分离出带有唾液酸LeA抗原的粘蛋白型糖蛋白（SL-GP）。 SL-GP以Ca2-和sialylLeA抗原依赖性方式与内皮细胞上的E-选择素结合。为了检查由连接引起的E-选择蛋白的代谢变化，用32P-磷酸或35S-Met和35S-Cys标记内皮细胞。通过与SL-GP而非唾液酸LeA六糖连接，可增强E-选择蛋白一个或多个丝氨酸残基的磷酸化作用。在SL-GP存在下用35S-Met和35S-Cys脉冲标记E-选择素表明SL-GP连接可加速E-选择素的降解，但与SL-GP预连接后的标记显示E-选择素的降解E-选择素的合成增加。该合成可以反映对在预连接时降解的E-选择蛋白的补偿。这些结果表明SL-GP的连接增强了E-选择素的整体代谢，降解和合成明显平衡。

BACKGROUND & AIMS: :In a context of automation of cryo-electron microscopy, we developed a novel method for improving visibility of diffraction rings in the power spectra of cryo-electron micrographs of vitreous ice (without carbon film or high concentration of diffracting material). We used these enhanced spectra to semi-automatically detect and remove micrographs and/or local areas introducing errors in the global 3D map (drifted and charged areas) or those unable to increase global signal-to-noise ratio (non-diffracting areas). Our strategy also allows a detection of micrographs/areas with a strong astigmatism. These images should be removed when using algorithms that do not correct astigmatism. Our sorting method is simple and fast since it uses the normalized cross-correlation between enhanced spectra and their copies rotated by 90 degrees. It owes its success mainly to the novel pre-processing of power spectra. The improved visibility also allows an easier visual check of accuracy of sorting. We show that our algorithm can even improve the visibility of diffraction rings of cryo-electron micrographs of pure water. Moreover, we show that this visibility depends strongly on ice thickness. This algorithm is implemented in the Xmipp (open-source image processing package) and is freely available for implementation in any other software package.

背景与目标： ：在低温电子显微镜自动化的背景下，我们开发了一种新颖的方法，用于改善玻璃冰（无碳膜或高浓度衍射材料）的低温电子显微镜照片的功率谱中衍射环的可见性。我们使用这些增强的光谱来半自动检测和移除显微照片和/或局部区域，从而在全局3D地图（漂移和带电区域）或无法提高全局信噪比的区域（非衍射区域）引入误差。我们的策略还允许检测具有强烈散光的显微照片/区域。当使用无法校正像散的算法时，应删除这些图像。我们的排序方法简单快捷，因为它使用增强光谱与其旋转90度的副本之间的归一化互相关。它的成功主要归功于新颖的功率谱预处理。改进的可见性还可以使目视检查的准确性更加容易。我们证明了我们的算法甚至可以提高纯水冷冻电子显微照片的衍射环的可见性。此外，我们证明了这种能见度在很大程度上取决于冰的厚度。该算法在Xmipp（开源图像处理软件包）中实现，可免费用于任何其他软件包中。

BACKGROUND & AIMS: Assembly of fibronectin fibrils occurs at the surface of substrate-attached cells and is mediated by the first to the fifth type I modules in the N-terminal 70 kDa portion of the molecule. The first type III module (III1) of fibronectin, not present in the 70 kDa portion, contains a conformation-dependent binding site for the 70 kDa N-terminal region of fibronectin, suggesting that the III1 module on cell-surface fibronectin may serve as a binding site for fibronectin's N-terminus on substrate-attached cells. To explore this possiblility, we compared the ability of mutant recombinant 70 kDa proteins containing deletions of one or several of the first five type I modules to bind to fibroblasts and to III1. Proteins containing the fourth and fiftBiomolecular Chemistry and Medicine, University of Wisconsin, Madison, WI 53706U.S.A. Assembly of fibronectin fibrils occurs at the surface of substrate-attached cells and is mediated by the first to the fifth type I modules in the N-terminal 70 kDa portion of the molecule. The first type III module (III1) of fibronectin, not present in the 70 kDa portion, contains a conh as 70 kDa deletion mutants lacking I4 and I5 also bound to the cell surface, and deletion mutants lacking I1-3 and I4-5 both competed only partially for binding of 125I-labelled fibronectin or 70 kDa protein. These data indicate that the N-terminal part of fibronectin binds to III1 via I4 and I5 and that interactions in addition to that of I4 and I5 with III1 are important for cell-surface-mediated fibronectin polymerization.

背景与目标： 纤连蛋白原纤维的组装发生在附着有底物的细胞表面，并由分子的N端70 kDa部分中的第一至第五类I模块介导。纤连蛋白的第一个III型模块（III1）（不存在于70 kDa的部分中）包含纤连蛋白70 kDa N端区域的构象依赖性结合位点，表明细胞表面纤连蛋白上的III1模块可以作为底物附着细胞上纤连蛋白N末端的结合位点。为了探讨这种可能性，我们比较了包含前五个I型模块中一个或多个缺失的突变重组70 kDa蛋白与成纤维细胞和III1结合的能力。含有第四和第五种蛋白质的蛋白质生物分子化学和医学，威斯康星大学麦迪逊分校，威斯康星州53706纤连蛋白原纤维的组装发生在附着有底物的细胞表面，并由分子的N端70 kDa部分中的第一至第五类I模块介导。纤连蛋白的第一个III型模块（III1）（不存在于70 kDa的部分）包含一个conh，因为缺少I4和I5的70 kDa缺失突变体也与细胞表面结合，而缺少I1-3和I4-5的缺失突变体都存在仅部分竞争结合125 I标记的纤连蛋白或70 kDa蛋白。这些数据表明纤连蛋白的N末端部分通过I4和I5与III1结合，并且除了I4和I5之外，与III1的相互作用对于细胞表面介导的纤连蛋白聚合也很重要。