中药治疗中风的分子靶点

“中风”是中医学对急性脑血管疾病的统称,具有极高的死亡率和致残率。中医药治疗中风有着悠久的历史,临床实验也证实了其疗效。然而由于中药常常需要多味药物联合使用,其有效成分很难明确,对其有效性评价具有挑战性,因此很难将中药制剂推向世界。综述中药治疗中风的分子靶点作用,列举了一些可能起效的天然化学物质,调查结果表明多成分多靶点的中药理论具有科学性。现代分子医学和传统中医理论的结合能促进医学界的广泛交流,值得深入探讨。     

Interaction of the C-terminal tail region of the metabotropic glutamate receptor 7 with the protein kinase C substrate PICK1

Group III metabotropic glutamate receptors (mGluRs) are highly enriched in the presynaptic terminals of glutamatergic synapses where they mediate feedback inhibition of neurotransmitter release. Here, we used the yeast two-hybrid system to identify a direct interaction of the C-terminal tail region of mGluR7 with the rat homologue of the protein kinase C substrate PICK1. This interaction is specifically mediated by the very C-terminal amino acids of the receptor and can be reconstituted in human embryonic kidney 293 cells by transfection of full-length mGluR7 and PICK1 cDNAs. Quantitative beta-galactosidase assays revealed that among the different group III mGluRs, mGluR7 is the major PICK1 binding partner although other subfamily members can also interact with PICK1. These data indicate that PDZ domain-containing proteins might contribute to the presynaptic localization of group III mGluRs.     

Expression of PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK) in human urinary bladder transitional cell carcinoma

The objective of this study was to evaluate the expression pattern of PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK) and its clinical significance in human bladder cancer (BC).     

Human papillomavirus (HPV)‐18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein

High‐risk human papillomavirus (HPV) infection is the principal risk factor for the development of cervical cancer. The HPV E6 oncoprotein has the ability to target and interfere with several PSD‐95/DLG/ZO‐1 (PDZ) domain‐containing proteins that are involved in the control of cell polarity. This function can be significant for E6 oncogenic activity because a deficiency in cell polarisation is a marker of tumour progression. The establishment and control of polarity in epithelial cells depend on the correct asymmetrical distribution of proteins and lipids at the cell borders and on specialised cell junctions. In this report, we have investigated the effects of HPV E6 protein on the polarity machinery, with a focus on the PDZ partitioning defective 3 (Par3) protein, which is a key component of tight junctions (TJ) and the polarity network. We demonstrate that E6 is able to bind and induce the mislocalisation of Par3 protein in a PDZ‐dependent manner without significant reduction in Par3 protein levels. In addition, the high‐risk HPV‐18 E6 protein promotes a delay in TJ formation when analysed by calcium switch assays. Taken together, the data presented in this study contribute to our understanding of the molecular mechanism by which HPVs induce the loss of cell polarity, with potential implications for the development and progression of HPV‐associated tumours.     

Protein interacting with C kinase and neurological disorders

Best known for its interaction with the α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor subunit GluA2 and for its influence on excitatory synapse activity, the protein interacting with C kinase, PICK1, is the focus of considerable attention from neurobiologists. Indeed, this PSD‐95/DlgA/ZO‐1 (PDZ) domain‐containing protein has been shown to interact with a wide variety of neurotransmitter receptors, transporters, and enzymes, including glutamate and nicotinic acetylcholine receptors, dopamine and glutamate transporters, and the enzyme serine racemase. Through its lipid binding domain, PICK1 is targeted to the inner surface of the cell membrane where it contributes to anchoring these partners and thereby influences their synaptic localization and function. Under pathological conditions, the regulation of some PICK1‐interacting partners is altered, pointing to an involvement of PICK1 in neurological disorders. Also, genetic or pharmacological manipulations of PICK1 expression, localization, or function have been shown to influence several physiological or pathological processes in which putative PICK1 partners are involved. This review will summarize recent experimental observations that highlight the involvement of PICK1 in neurological disorders, including schizophrenia, Parkinson's disease, epilepsy, chronic pain, drug abuse, and amyotrophic lateral sclerosis. Synapse 67:532–540, 2013. © 2013 Wiley Periodicals, Inc.     

Structural Basis of the Avian Influenza NS1 Protein Interactions with the Cell Polarity Regulator Scribble

Scribble is a highly conserved regulator of cell polarity, a process that enables the generation of asymmetry at the cellular and tissue level in higher organisms. Scribble acts in concert with Disc-large (Dlg) and Lethal-2-giant larvae (Lgl) to form the Scribble polarity complex, and its functional dysregulation is associated with poor prognosis during viral infections. Viruses have been shown to interfere with Scribble by targeting Scribble PDZ domains to subvert the network of interactions that enable normal control of cell polarity via Scribble, as well as the localisation of the Scribble module within the cell. The influenza A virus NS1 protein was shown to bind to human Scribble (SCRIB) via its C-terminal PDZ binding motif (PBM). It was reported that the PBM sequence ESEV is a virulence determinant for influenza A virus H5N1 whilst other sequences, such as ESKV, KSEV and RSKV, demonstrated no affinity towards Scribble. We now show, using isothermal titration calorimetry (ITC), that ESKV and KSEV bind to SCRIB PDZ domains and that ESEV unexpectedly displayed an affinity towards all four PDZs and not just a selected few. We then define the structural basis for the interactions of SCRIB PDZ1 domain with ESEV and ESKV PBM motifs, as well as SCRIB PDZ3 with the ESKV PBM motif. These findings will serve as a platform for understanding the role of Scribble PDZ domains and their interactions with different NS1 PBMs and the mechanisms that mediate cell polarity within the context of the pathogenesis of influenza A virus.     

Molecular interactions of the plasma membrane calcium ATPase 2 at pre- and post-synaptic sites in rat cerebellum

The plasma membrane calcium extrusion mechanism, PMCA (plasma membrane calcium ATPase) isoform 2 is richly expressed in the brain and particularly the cerebellum. Whilst PMCA2 is known to interact with a variety of proteins to participate in important signalling events [Strehler EE, Filoteo AG, Penniston JT, Caride AJ (2007) Plasma-membrane Ca(2+) pumps: structural diversity as the basis for functional versatility. Biochem Soc Trans 35 (Pt 5):919–922], its molecular interactions in brain synapse tissue are not well understood. An initial proteomics screen and a biochemical fractionation approach identified PMCA2 and potential partners at both pre- and post-synaptic sites in synapse-enriched brain tissue from rat. Reciprocal immunoprecipitation and GST pull-down approaches confirmed that PMCA2 interacts with the post-synaptic proteins PSD95 and the NMDA glutamate receptor subunits NR1 and NR2a, via its C-terminal PDZ (PSD95/Dlg/ZO-1) binding domain. Since PSD95 is a well-known partner for the NMDA receptor this raises the exciting possibility that all three interactions occur within the same post-synaptic signalling complex. At the pre-synapse, where PMCA2 was present in the pre-synapse web, reciprocal immunoprecipitation and GST pull-down approaches identified the pre-synaptic membrane protein syntaxin-1A, a member of the SNARE complex, as a potential partner for PMCA2. Both PSD95–PMCA2 and syntaxin-1A–PMCA2 interactions were also detected in the molecular and granule cell layers of rat cerebellar sagittal slices by immunohistochemistry. These specific molecular interactions at cerebellar synapses may allow PMCA2 to closely control local calcium dynamics as part of pre- and post-synaptic signalling complexes.     

大鼠PDZ1-FLAG的亚克隆及pcDNA3.1载体的构建

目的亚克隆大鼠PDZ1-FLAG基因片段并构建pcDNA3.1载体.方法以pAdTrack-CMV-PDZ1为模板,采用PCR法获得PDZ1-FLAG的双链DNA;与pcDNA3.1载体用T4 DNA连接酶连接;连接产物转化大肠杆菌JM109进行筛选、序列测定.结果①得到了PDZ1-FLAG的双链DNA;②酶切鉴定能观察到PDZ1-FLAG和pcDNA3.1两条带;③PDZ1-FLAG测序图谱与文献报道完全一致.结论获得了含目的基因PDZ1-FLAG的pcDNA3.1载体.     

中药治疗中风的分子靶点

“中风”是中医学对急性脑血管疾病的统称,具有极高的死亡率和致残率。中医药治疗中风有着悠久的历史,临床实验也证实了其疗效。然而由于中药常常需要多味药物联合使用,其有效成分很难明确,对其有效性评价具有挑战性,因此很难将中药制剂推向世界。综述中药治疗中风的分子靶点作用,列举了一些可能起效的天然化学物质,调查结果表明多成分多靶点的中药理论具有科学性。现代分子医学和传统中医理论的结合能促进医学界的广泛交流,值得深入探讨。