Proline-rich tyrosine kinase 2 and its inhibitor PRNK

Proline-rich tyrosine kinase 2 (Pyk2) is a nonreceptor protein tyrosine kinase,which is also known as Ca2 +-dependent tyrosine kinase or related adhesion focal tyrosine kinase.Pyk2 activation exerts a critical regulatory mechanism for various physiological processes including cytoskeleton function,regulation of cell growth and death,modulation of ion channels and multiple signaling events.However,mechanisms underlying the functional diversity of Pyk2 are not clear.A Pyk2 isoform that encodes only part of the C-terminal domain of Pyk2,named as PRNK (Pyk2-related non-kinase),acts as a dominant-negative inhibitor of Pyk2-dependent signaling by displacing Pyk2 from focal adhesions.Research on functional PRNK probably provides new potential inhibitory tool targeting Pyk2 and makes it possible to explore more of Pyk2 pathological mechanism.PRNK is a promising candidate targeting Pyk2 modulation.This review focuses on the functional investigation of Pyk2 and its structure and localization,including recent research with inhibitory strategies targeting Pyk2 by the method of PRNK.

On the Distribution of Acidic Proline-rich Proteins Phenotypes in Chinese Han Population in Liaoning Area

The distribution of salivary acidic proline-rich proteins pheno-types was investigated by using the ultra-thin PAGIEF technique in 258 ChineseHan populations in Liaoning area. The gene frequencies were as follows: Pr^10.8101, Pr^20.1899; Db^+0.0416, Db^-0.9584; Pa^+0.1717, Pa^-0.8283; PIF^+0.6647, PIF^-0.3353. The observed numbers of the phenotypes are in good a-greement with the expected numbers under the Hardy-Weinberg equilibrium.The gene frequencies among the Chinese and other populations are compared.

The involvement of proline-rich protein Mus musculus predicted gene 4736 in ocular surface functions

AIM: To research the two homologous predicted proline -rich protein genes, Mus musculus predicted gene 4736 (MP4) and proline-rich protein BstNI subfamily 1 (Prb1) which were significantly upregulated in cultured corneal organs when encountering fungal pathogen preparations. This study was to confirm the expression and potential functions of these two genes in ocular surface. METHODS: A Pseudomonas aeruginosa keratitis model was established in Balb/c mice. One day post infection, mRNA level of MP4 was measured using real-time polymerase chain reaction (PCR), and MP4 protein detected by immunohistochemistry (IHC) or Western blot using a customized polyclonal anti -MP4 antibody preparation. Lacrimal glands from normal mice were also subjected to IHC staining for MP4. An online bioinformatics program, BioGPS, was utilized to screen public data to determine other potential locations of MP4. RESULTS: One day after keratitis induction, MP4 was upregulated in the corneas at both mRNA level as measured using real -time PCR and protein levels as measured using Western blot and IHC. BioGPS analysis of public data suggested that the MP4 gene was most abundantly expressed in the lacrimal glands, and IHC revealed that normal murine lacrimal glands were positive for MP4 staining. CONCLUSION: MP4 and Prb1 are closely related with the physiology and pathological processes of the ocular surface. Considering the significance of ocular surface abnormalities like dry eye, we propose that MP4 and Prb1 contribute to homeostasis of ocular surface, and deserve more extensive functional and disease correlation studies.

PRGL:A cell wall proline-rich protein containning GASA domain in Gerbera hybrida

PRPs (proline-rich proteins) are a group of cell wall proteins characterized by their proline and hy- droproline-rich repetitive peptides. The expression of PRPs in plants is stimulated by wounding and environmental stress. GASA (gibberellic acid stimulated in Arabidopsis) proteins are small peptides sharing a 60 amino acid conserved C-terminal domain containing twelve invariant cysteine residues. Most of GASAs reported are localized to apoplasm or cell wall and their expression was regulated by gibberellins (GAs). It has been reported that, in French bean, these two proteins encoding by two distinct genes formed a two-component chitin-receptor involved in plant-pathogen interactions when plant was infected. We cloned a full-length cDNA of PRGL (proline-rich GASA-like) gene which encodes a protein containing both PRP and GASA-like domains. It is demonstrated that PRGL is a new protein with characteristics of PRP and GASA by analyzing its protein structure and gene expression.

人PRR11启动子的结构与功能初步分析

PRR11(proline-rich protein 11,PRR11)是我们最近发现的一个新的肿瘤相关基因.初步研究表明,PRR11参与细胞增殖、细胞周期和细胞癌变等多种生物学过程.为了进一步研究PRR11基因的转录调控机制并全面解析其功能,本研究对PRR11基因的启动子进行了克隆鉴定和初步分析.首先,应用5'RACE(rapid amplification of cDNA ends,cDNA末端快速扩增)技术鉴定了PRR11基因的转录起始位点,发现了其具有多个转录起始位点.通过PCR定向克隆和DNA blunting技术,构建了6个相互重叠并覆盖PRR11基因转录起始位点附近约2.0 kb区域的PRR 11基因启动子荧光素酶报告基因重组体.启动子活性分析表明,PRR 11基因启动子主要定位于转录起始位点附近-563 bp～+341 bp的区域内.采用转录因子结合位点预测分析软件分析表明,PRR 11基因启动子缺乏典型的TATA盒,但含有典型的GC盒、CCAAT盒以及潜在的经典转录因子E2F1和MYB的结合位点,提示Sp1、NF-Y、E2F1和MYB等经典转录因子可能参与PRR 11基因的转录调控.

Sequence Analysis of Type III Effector tccP and tccP2 Genes in Escherichia coli O157:H7 from Chinese Water-chestnut

[Objective] This study aimed to analyze the type III effector tccP and tccP2 genes in Escherichia coli O157：H7 from Chinese water-chestnut. [Method] Gene-specific and locus-specific primers were utilized to amplify tccP/tccP2 and their flanking regions for sequence analysis. [Result] E. coli O157：H7 CWN11 harbored intact tccP and tccP2 genes, however, the number of proline-rich repeats in tccP gene was only one that probably resulted in biological incapability, whereas, the tccP2 gene consisted of five and half proline-rich repeats and could encode functional protein. [Conclusion] Here, we reported the first sequence of tccP gene that consisted of only one proline-rich repeat and tccP2 was assumed to play a crucial role in colonization and subsequent signaling cascades.

Viral proteins and Src family kinases: Mechanisms of pathogenicity from a “liaison dangereuse”

To complete their life cycle and spread, viruses interfere with and gain control of diverse cellular processes, this most often occurring through interaction between viral proteins(VPs) and resident protein partners. Among the latter, Src family kinases(SFKs), a class of non-receptor tyrosine kinases that contributes to the conversion of extracellular signals into intracellular signaling cascades and is involved in virtually all cellular processes, have recently emerged as critical mediators between the cell's infrastructure and the viral demands. In this scenario, structural or ex novo synthesized VPs are able to bind to the different domains of these enzymes through specific short linear motifs present along their sequences. Proline-rich motifs displaying the conserved minimal consensus PxxP and recognizing the SFK Src homology(SH)3 domain constitute a cardinal signature for the formation of multiprotein complexes and this interaction may promote phosphorylation of VPs by SFKs, thus creating phosphotyrosine motifs that become a docking site for the SH2 domains of SFKs or other SH2 domain-bearing signaling molecules. Importantly, the formation of these assemblies also results in a change in the activity and/or location of SFKs, and these events are critical in perturbing key signalingpathways so that viruses can utilize the cell's machinery to their own benefit. In the light of these observations, although VPs as such, especially those with enzyme activity, are still regarded as valuable targets for therapeutic strategies, multiprotein complexes composed of viral and host cell proteins are increasingly becoming objects of investigation with a view to deeply characterize the structural aspects that favor their formation and to develop new compounds able to contrast viral diseases in an alternative manner.

Increased Electrophoretic Mobility of Long-Type GATA-6 Transcription Factor upon Substitution of Its PEST Sequence

The transcriptional factor GATA-6 gene produces two translational isoforms from a single mRNA through ribosomal leaky scanning. L-type GATA-6 has an extension of 146 amino acid residues at its amino terminus. In the extension, there is a unique PEST sequence (Glu31-Cys46), which is composed of an amino terminal Pro-rich segment and a carboxyl terminal Ser-cluster. Substitution of either half of the PEST sequence with Ala residues by cassette mutagenesis reduced the apparent molecular size of L-type GATA-6 on SDS-polyacrylamide gel-electrophoresis. However, the effect of substitution of the Pro-rich segment was much more significant;the mobility increase of the Pro-rich segment on the gel was 13% while that of the Ser-cluster was 8%. Substitution of each amino acid residue demonstrated that the effect of Pro substitution is greater than that of the Ser and Thr residues. Such increased mobility of L-type GATA-6 in the presence of a detergent may apparently correlate with the decrease in transcription activity in vivo as determined by means of luciferase reporter gene assay. The activity of ΔAla (with Ala residues instead of the PEST sequence) was reduced to one fifth of that of ΔA (with the PEST sequence). These results suggest that the PEST sequence of L-type GATA-6 does not function as a constitutive protein degradation signal, but rather plays structural and functional roles in the activation of gene expression on the GATA responsive promoter.

β-catenin/Tcf Signaling in Squamous Differentiation of Porcine Airway Epithelial Cells

For a preliminary study of the role of β-catenin/Tcf signaling in squamous differentiation of airway （tracheobronchial） epithelial cells, a stable mutant of β-catenin was transfected into primarily cultured porcine airway epithelial cells. Western blotting revealed that exogenous protein was observed in large quantity in cytoplasm and nucleus, When co-transfected with Tcf luciferase reporter plasmids, β-catenin mutant increased the reporter＇s transcriptional activities. However, mRNA expression of a squamous differentiation marker, small proline-rich protein （SPRP）, was not elevated, as shown by reverse transcription-polymerase chain reaction. These findings suggest that β-catenin/Tcf signaling may not be directly involved in the squamous differentiation of porcine airway epithelial cells.

PRRT2 Mutation and Serum Cytokines in Paroxysmal Kinesigenic Dyskinesia

Objective Paroxysmal kinesigenic dyskinesia(PKD)is a rare movement disorder PRRT2 gene mutations have been reported to cause PKD.However,the pathophysiological mechanism of PKD remains unclear,and it is unknown whether an inflammatory response is involved in the occurrence of this disease.We aimed to investigate the symptomatology,genotype,and serum cytokines of patients with PKD.Methods We recruited 21 patients with PKD,including 7 with familial PKD and 14 with sporadic PKD.Their clinical features were investigated,and blood samples were collected,and PRRT2 mutations and cytokine levels were detected.Results The mean age at PKD onset was 12.3±2.2 years old.Dystonia was the most common manifestation of dyskinesia,and the limbs were the most commonly affected parts.All attacks were induced by identifiable kinesigenic triggers,and the attack durations were brief(<1 min).Four different mutations from 9 probands were identified in 7 familial cases(71.4%)and 14 sporadic cases(28.6%).Two of these mutations(c.649dupC,c.620_621delAA)had already been reported,while other 2(c.1018_1019delAA,c.1012+1G>A)were previously undocumented.The tumor necrosis factor(TNF)-αlevel in the PKD group was significantly higher than that in the age-and sex-matched control group(P=0.025).There were no significant differences in the interleukin(IL)-1β,IL-2R,IL-6,IL-8,or IL-10 levels between the two groups.Conclusion In this study,we summarized the clinical and genetic characteristics of PKD.We found that the serum TNF-αlevels were elevated in patients clinically diagnosed with PKD,suggesting that an inflammatory response is involved in the pathogenesis of PKD.

Endophilin isoforms have distinct characteristics in interactions with N-type Ca^(2+) channels and dynamin I

Objective Formation of the endophilin II-Ca 2＋ channel complex is Ca 2＋ -dependent in clathrin-mediated endocytosis. However, little is known about whether the other two endophilin isoforms have the same features. The present study aimed to investigate the characteristics of the interactions of all three isoforms with Ca 2＋ channels and dynamin I. Methods N-type Ca 2＋ channel C-terminal fragments （NCFs） synthesized with a 3 H-leucine-labeled kit, were incubated with endophilin-GST fusion proteins, followed by pull-down assay. Results were counted on a scintillation counter. In addition, the different endophilin isoforms were each co-transfected with dynamin I into 293T cells, followed by flow cytometry and co-immunoprecipitation assay. Immunostaining was performed and an image analysis program was used to evaluate the overlap coefficient of cells expressing endophilin and dynamin I. Results All three isoforms interacted with NCF. Endophilins I and II demonstrated clear Ca 2＋ -dependent interactions with NCF, whereas endophilin III did not. Co-immunoprecipitation showed that, compared to endophilin I/II, the interaction between endophilin III and dynamin I was significantly increased. Similar results were obtained from flow cytometry. Furthermore, endophilin III had a higher overlap coefficient with dynamin I in co-transfected 293T cells. Conclusion Endophilin isoforms have distinct characteristics in interactions with NCF and dynamin I. Endophilin III binding to NCF is Ca 2＋ -independent, implying that it plays a different role in clathrin-mediated endocytosis.