Recently Identified Forms of Epidermolysis Bullosa

Epidermolysis bullosa (EB) comprises a collection of clinically diverse inherited blistering diseases that affect the skin and, in some subtypes, mucous membranes and other organs. Currently classified into four main subtypes (EB simplex, junctional EB, dystrophic EB, and Kindler syndrome, mainly based on the level of skin cleavage), the spectrum of EB extends to more than 30 clinical subtypes with pathogenic mutations in at least 18 distinct genes. This review focuses on three recent additions to variants of EB: all are autosomal recessive, and result from mutations in either DST-e (coding for epidermal dystonin, also known as the 230 kDa bullous pemphigoid antigen, BP230), EXPH5 (coding for exophilin-5, also known as Slac2-b), or ITGA3 (coding for the integrin alpha-3 subunit). Each of these new forms of EB is reviewed with respect to the initial gene discovery, clinical features, the current mutation database, and skin pathology. Awareness of these recently described forms of EB is helpful in the clinical evaluation of patients with EB and in defining genotype-phenotype correlation for inherited blistering skin diseases.

Comparison of microRNA expression profiles in HCC-derived microvesicles and the parental cells and evaluation of their roles in HCC / 华中科技大学学报（医学）（英德文版）

To determine whether the microRNAs (miRNAs) contained in cancer-derived microvesicles (MVs) mirror those of the parental tumor cells, we compared the miRNA expression profiles of MVs derived from their parental hepatocellular carcinoma (HCC) cells. The presence and levels of 888 miRNAs from SMMC-7721 cells and MVs were detected by Agilent miRNA microarray analysis. Four selected miRNAs were verified by real time qRT-PCR. Furthermore, the genes of the miRNAs were bioinformatically identified to explore potential roles of the miRNAs in HCC microenvironment. Our results showed that miRNAs expression profiles of MVs derived from HCC were significantly changed. Of all the miRNAs tested, 148 miRNAs were co-expressed in MVs and SMMC-7721 cells, only 121 and 15 miRNAs were detected in MVs and SMMC-7721 cells, respectively. Among the 148 co-expressing miRNAs, 48 miRNAs had the similar expression level and 6 of them were supposed to be oncogenic or suppressive miRNAs. According to the target prediction by Quantile Algorithm method, these miRNAs may regulate 3831 genes which were closely related to cell cycle, apoptosis and oncogenesis, and 78 were known tumor suppressors or oncogenes. Gene ontology (GO) analysis indicated that 3831 genes were mainly associated with nucleic acid binding, cell death, cell adhesion. MVs containing miRNAs, released into the HCC microenvironment, bear the characteristic miRNAs of the original cells and might participate in cancer progression.

The hydrophobic amino acids involved in the interdomain association of phospholipase D1 regulate the shuttling of phospholipase D1 from vesicular organelles into the nucleus

Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to generate the lipid second messenger, phosphatidic acid. PLD is localized in most cellular organelles, where it is likely to play different roles in signal transduction. PLD1 is primarily localized in vesicular structures such as endosomes, lysosomes and autophagosomes. However, the factors defining its localization are less clear. In this study, we found that four hydrophobic residues present in the N-terminal HKD catalytic motif of PLD1, which is involved in intramolecular association, are responsible for vesicular localization. Site-directed mutagenesis of the residues dramatically disrupted vesicular localization of PLD1. Interestingly, the hydrophobic residues of PLD1 are also involved in the interruption of its nuclear localization. Mutation of the residues increased the association of PLD1 with importin-beta, which is known to mediate nuclear importation, and induced the localization of PLD1 from vesicles into the nucleus. Taken together, these data suggest that the hydrophobic amino acids involved in the interdomain association of PLD1 are required for vesicular localization and disturbance of its nuclear localization.

Dynamin-mediated endocytic process contributes to neuronal nitric oxide synthase-mediated regulation of cardiac contraction / 生理学报

Nitric oxide synthases (NOSs) play complex roles in the regulation of cardiac excitation contraction coupling under basal and stressed conditions. Herein, using the recording approach for intracellular calcium transient and synchronous myocyte contraction, the potential mechanism for NOSs-mediated cardiomyocyte contraction was explored. We found that selective inhibition of neuronal NOS (nNOS) with 100 µmol/L spermidine markedly enhanced the cardiomyocyte twitch [control: (10.5 ± 0.21)%; nNOS inhibition: (12.4 ± 0.18)%] and calcium transient [control: (0.27 ± 0.03)%; nNOS inhibition: (0.42 ± 0.01)%], but slowed the relengthening of twitch [control: (25.2 ± 1.3) ms; nNOS inhibition: (53 ± 2.8) ms] and the calcium transient decay [control: (129 ± 4.3) ms; nNOS inhibition: (176 ± 7.1) ms], which was similar to that by dynamin inhibition with 30 µmol/L dynasore. The nNOS inhibition- or dynasore-mediated effects could be rescued by an NO donor, S-Nitroso-N-acetylpenicillamine (SNAP). Our data suggest that the selective nNOS-mediated regulation of cardiac contractile activity may partly involve the dynamin-mediated endocytic mechanism.

Intramanchette transport during primate spermiogenesis: expression of dynein, myosin Va, motor recruiter myosin Va, VIIa-Rab27a/b interacting protein, and Rab27b in the manchette during human and monkey spermiogenesis / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To show whether molecular motor dynein on a microtubule track, molecular motor myosin Va, motor recruiter myosin Va, VIIa-Rab27a/b interacting protein (MyRIP), and vesicle receptor Rab27b on an F-actin track were present during human and monkey spermiogenesis involving intramanchette transport (IMT).</p><p><b>METHODS</b>Spermiogenic cells were obtained from three men with obstructive azoospermia and normal adult cynomolgus monkey (Macaca fascicularis). Immunocytochemical detection and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the proteins were carried out. Samples were analyzed by light microscope.</p><p><b>RESULTS</b>Using RT-PCR, we found that dynein, myosin Va, MyRIP and Rab27b were expressed in monkey testis. These proteins were localized to the manchette, as shown by immunofluorescence, particularly during human and monkey spermiogenesis.</p><p><b>CONCLUSION</b>We speculate that during primate spermiogenesis, those proteins that compose microtubule-based and actin-based vesicle transport systems are actually present in the manchette and might possibly be involved in intramanchette transport.</p>

Use of a synthetic lethal screen to identify genes related to TIF51A in Saccharomyces cerevisiae

The putative eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for cell viability and the only cellular protein known to contain the unusual amino acid residue hypusine. eIF5A has been implicated in translation initiation, cell proliferation, nucleocytoplasmic transport, mRNA decay, and actin polarization, but the precise biological function of this protein is not clear. However, eIF5A was recently shown to be directly involved with the translational machinery. A screen for synthetic lethal mutations was carried out with one of the temperature-sensitive alleles of TIF51A (tif51A-3) to identify factors that functionally interact with eIF5A and revealed the essential gene YPT1. This gene encodes a small GTPase, a member of the rab family involved with secretion, acting in the vesicular trafficking between endoplasmatic reticulum and the Golgi. Thus, the synthetic lethality between TIF51A and YPT1 may reveal the connection between translation and the polarized distribution of membrane components, suggesting that these proteins work together in the cell to guarantee proper protein synthesis and secretion necessary for correct bud formation during G1/S transition. Future studies will investigate the functional interaction between eIF5A and Ypt1 in order to clarify this involvement of eIF5A with vesicular trafficking.

Kinesin Superfamily KIF5 Proteins Bind to betaIII Spectrin

The kinesin proteins (KIFs) make up a large superfamily of molecular motors that transport cargo such as vesicles, protein complexes, and organelles. KIF5 is a heterotetrameric motor that conveys vesicles and plays an important role in neuronal function. Here, we used the yeast two-hybrid system to identify the neuronal protein (s) that interacts with the tail region of KIF5 and found a specific interaction with betaIII spectrin. The amino acid residues between 1394 and 1774 of betaIII spectrin were required for the interaction with KIF5C. betaIII spectrin also bound to the tail region of neuronal KIF5A and ubiquitous KIF5B but not to other kinesin family members in the yeast two-hybrid assay. In addition, these proteins showed specific interactions, confirmed by GST pull-down assay and co-immunoprecipitation. betaIII spectrin interacted with GST-KIF5 fusion proteins, but not with GST alone. An antibody to betaIII spectrin specifically co-immunoprecipitated KIF5s associated with betaIII spectrin from mouse brain extracts. These results suggest that KIF5 motor proteins transport vesicles or organelles that are coated with betaIII spectrin.