Lingo2 variants associated with essential tremor and Parkinson��s disease

LINGO2, a member of LRR gene family, has been linked with both Essential tremor (ET) and Parkinson's disease (PD). However, there is a lack of conclusive evidence regarding the etiologic role of LINGO2 genetic variants. We investigated the association of LINGO2 variants with ET and PD in two independent Asian countries. A total of 1,262 subjects comprising 499 controls, 436 PD patients, and 327 ET patients were included. Eight LINGO2 variants, including four single-nucleotide polymorphisms (SNPs) and four coding variants, were initially analyzed in one Asian population. SNPs that showed positive association were then replicated in the second independent Asian population, and a pooled analysis was carried out. Out of the eight variants, two SNPs (rs7033345 and rs10812774) revealed significant or strong positive trend in the first Asian population, and these were analyzed in the second Asian population. In the pooled analysis, the CC genotype at rs7033345 had a higher risk of developing PD (OR?=?1.67, 95% CI?=?1.18, 2.35, p?=?0.003) and ET (OR?=?1.50, 95% CI?=?1.02, 2.20, p?=?0.04) under a recessive model. The C allele at rs10812774 increased the risk of ET (OR?=?1.56 95% CI?=?1.10, 2.22, p?=?0.01) via a recessive model. The effect size and direction of trend were in the same direction in each of the two populations. Our study demonstrated for the first time that rs7033345 is associated with PD and ET and rs10812774 with ET among Asians, suggesting that LINGO2 might act as a susceptibility gene for both conditions.     

Molecular cloning and sequence analysis of aggretin, a collagen-like platelet aggregation inducer.

A cDNA library derived from the Malayan-pit-viper (Calloselasma rhodostoma) venom gland was constructed in the phagemid vector. Using the information of the N-terminal amino acid sequences of two subunits of aggretin, synthetic mixed-base oligonucleotides were employed as a screening probe for colony hybridization. Separate cDNA clones encoding for the alpha and beta chains of aggretin were isolated and sequenced. The results revealed that mature alpha and beta chains contain 136 and 123 amino acid residues, respectively. Aggretin subunits show high degrees of identity with respective subunits (50-60% for alpha, 49-58% for beta) of C-type lectin-like snake venoms. The identity to rattlesnake lectin is relatively lower (i.e., 39 and 30%). All cysteine residues in each chain of aggretin are well conserved and located at the positions corresponding to those of C-type lectins. Thus, three intracatenary disulfide bridges and an interchain disulfide bond between Cys83(alpha) and Cys75(beta) may be allocated. This is the first report regarding the entire sequence of venom GPIa/IIa agonist. According to the alignment of amino acid sequences, hypervariable regions among these C-type lectin-like proteins were revealed. These hypervariable regions are proposed to be the counterparts directly interacting with different receptors or different domains of a receptor on the surface of platelet.     

Involvement of Endoplasmic Reticulum Stress in TULP1 Induced Retinal Degeneration

Inherited retinal disorders (IRDs) result in severe visual impairments in children and adults. A challenge in the field of retinal degenerations is identifying mechanisms of photoreceptor cell death related to specific genetic mutations. Mutations in the gene TULP1 have been associated with two forms of IRDs, early-onset retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA). TULP1 is a cytoplasmic, membrane-associated protein shown to be involved in transportation of newly synthesized proteins destined for the outer segment compartment of photoreceptor cells; however, how mutant TULP1 causes cell death is not understood. In this study, we provide evidence that common missense mutations in TULP1 express as misfolded protein products that accumulate within the endoplasmic reticulum (ER) causing prolonged ER stress. In an effort to maintain protein homeostasis, photoreceptor cells then activate the unfolded protein response (UPR) complex. Our results indicate that the two major apoptotic arms of the UPR pathway, PERK and IRE1, are activated. Additionally, we show that retinas expressing mutant TULP1 significantly upregulate the expression of CHOP, a UPR signaling protein promoting apoptosis, and undergo photoreceptor cell death. Our study demonstrates that the ER-UPR, a known mechanism of apoptosis secondary to an overwhelming accumulation of misfolded protein, is involved in photoreceptor degeneration caused by missense mutations in TULP1. These observations suggest that modulating the UPR pathways might be a strategy for therapeutic intervention.     

Expression,sorting, and segregation of Golgi proteins during germ cell differentiation in the testis

The molecular basis of changes in structure, cellular location, and function of the Golgi apparatus during male germ cell differentiation is unknown. To deduce cognate Golgi proteins, we isolated germ cell Golgi fractions, and 1318 proteins were characterized, with 20 localized in situ. The most abundant protein, GL54D of unknown function, is characterized as a germ cell–specific Golgi-localized type II integral membrane glycoprotein. TM9SF3, also of unknown function, was revealed to be a universal Golgi marker for both somatic and germ cells. During acrosome formation, several Golgi proteins (GBF1, GPP34, GRASP55) localize to both the acrosome and Golgi, while GL54D, TM9SF3, and the Golgi trafficking protein TMED7/p27 are segregated from the acrosome. After acrosome formation, GL54D, TM9SF3, TMED4/p25, and TMED7/p27 continue to mark Golgi identity as it migrates away from the acrosome, while the others (GBF1, GPP34, GRASP55) remain in the acrosome and are progressively lost in later steps of differentiation. Cytoplasmic HSP70.2 and the endoplasmic reticulum luminal protein-folding enzyme PDILT are also Golgi recruited but only during acrosome formation. This resource identifies abundant Golgi proteins that are expressed differentially during mitosis, meiosis, and postacrosome Golgi migration, including the last step of differentiation.     

L-amino-acid oxidase from the Malayan pit viper Calloselasma rhodostoma. Comparative sequence analysis and characterization of active and inactive forms of the enzyme.

Here we report the cDNA-deduced amino-acid sequence of L-amino-acid oxidase (LAAO) from the Malayan pit viper Calloselasma rhodostoma, which shows 83% identity to LAAOs from the Eastern and Western diamondback rattlesnake (Crotalus adamanteus and Crotalus atrox, respectively). Phylogenetic comparison of the FAD-dependent ophidian LAAOs to FAD-dependent oxidases such as monoamine oxidases, D-amino-acid oxidases and tryptophan 2-monooxygenases reveals only distant relationships. Nevertheless, all LAAOs share a highly conserved dinucleotide-binding fold with monoamine oxidases, tryptophan 2-monooxygenases and various other proteins that also may have a requirement for FAD. In order to characterize Ca. rhodostoma LAAO biochemically, the enzyme was purified from snake venom to apparent homogeneity. It was found that the enzyme undergoes inactivation by either freezing or increasing the pH to above neutrality. Both inactivation processes are fully reversible and are associated with changes in the UV/visible range of the flavin absorbance spectrum. In addition, the spectral characteristics of the freeze-and pH-induced inactivated enzyme are the same, indicating that the flavin environments are similar in the two inactive conformational forms. Monovalent anions, such as Cl(-), prevent pH-induced inactivation. LAAO exhibits typical flavoprotein oxidase properties, such as thermodynamic stabilization of the red flavin semiquinone radical and formation of a sulfite adduct. The latter complex as well as the complex with the competitive substrate inhibitor, anthranilate, were only formed with the active form of the enzyme indicating diminished accessibility of the flavin binding site in the inactive form(s) of the enzyme.