Zhou Q et al. (1997) J Biol Chem "Molecular cloning of human plasma membrane phospholipid scramblase. A protein mediating transbilayer movement of plasma membrane phospholipids."

Zhou Q, Wiedmer T, Luhm RA, Zhao J, Stout JG, Sims PJ

[J Biol Chem, 1997]

The rapid movement of phospholipids (PL) between plasma membrane leaflets in response to increased intracellular Ca2+ is thought to play a key role in expression of platelet procoagulant activity and in clearance of injured or apoptotic cells. We recently reported isolation of a approximately 37-kDa protein in erythrocyte membrane that mediates Ca2+-dependent movement of PL between membrane leaflets, similar to that observed upon elevation of Ca2+ in the cytosol (Basse, F., Stout, J. G., Sims, P. J., and Wiedmer, T. (1996) J. Biol. Chem. 271, 17205-17210). Based on internal peptide sequence obtained from this protein, a 1,445-base pair cDNA was cloned from a K-562 cDNA library. The deduced "PL scramblase" protein is a proline-rich, type II plasma membrane protein with a single transmembrane segment near the C terminus. Antibody against the deduced C-terminal peptide was found to precipitate the approximately 37-kDa red blood cell protein and absorb PL scramblase activity, confirming the identity of the cloned cDNA to erythrocyte PL scramblase. Ca2+-dependent PL scramblase activity was also demonstrated in recombinant protein expressed from plasmid containing the cDNA. Quantitative immunoblotting revealed an approximately 10-fold higher abundance of PL scramblase in platelet ( approximately 10(4) molecules/cell) than in erythrocyte ( approximately 10(3) molecules/cell), consistent with apparent increased PL scramblase activity of the platelet plasma membrane. PL scramblase mRNA was found in a variety of hematologic and nonhematologic cells and tissues, suggesting that this protein functions in all cells.

Sanchez AD et al. (2021) STAR Protoc "A proximity labeling protocol to probe proximity interactions in C.elegans."

Feldman JL, Sanchez AD

[STAR Protoc, 2021]

Enzyme-catalyzed proximity labeling (PL) has emerged as a critical approach for identifying protein-protein proximity interactions in cells; however, PL techniques were not historically practical in living multicellular organisms due to technical limitations. Here, we present a protocol for applying PL to living <i>C.elegans</i> using the biotin ligase mutant enzyme TurboID. We demonstrated PL in a tissue-specific and region-specific manner by focusing on non-centrosomal MTOCs (ncMTOCs) of intestinal cells. This protocol is useful for targeted <i>in vivo</i> protein network profiling. For complete details on the use and execution of this protocol, please refer to Sanchez et al. (2021).

Wang, Lianzijun et al. (2021) MicroPubl Biol

Qiu, Zhongqiang, Lee, Myeongwoo, Wang, Lianzijun

[MicroPubl Biol, 2021]

The amino acid sequence Arg-Gly-Asp (RGD) is a cell-binding motif for extracellular matrix proteins. Initially found in fibronectin, the RGD motif is also found in LAM-3/laminin &#945; chain in C. elegans. Laminin, a heterotrimeric glycoprotein, is a significant component of the basement membrane. Mutations in laminin subunits disrupt the extracellular matrix hence inhibit cell adhesion. This study aims to characterize the function of the RGD motif in lam-3/laminin &#945;. Two mutations, lam-3 RGE and lam-3 &#916;RGD, were generated. Our analysis of the mutants revealed that the RGD motif is involved in the motility of animals, suggesting that the cell-laminin interaction plays a role in regulating body contraction.

Mak JW et al. (1987) J Helminthol "Chemoprophylactic studies with ivermectin against subperiodic Brugia malayi infection in the leaf monkey, Presbytis cristata."

Mak JW, Suresh K, Lam PL, Rain AN

[J Helminthol, 1987]

Four Presbytis cristata were treated with oral ivermectin at the same time as the subcutaneous inoculation of 100 infective larvae monthly for three months. Two animals given 0.2 mg/kg monthly and two others given 0.3 mg/kg monthly as well as three control animals became patent for microfilaraemia. However, only 1% of the infective dose was recovered as adult worms from animals in the higher drug dosage group compared to 8.2% and 6.2% in the lower dosage and control groups respectively.

Mak JW et al. (1990) Acta Trop "Experimental infection of the leaf-monkeys, Presbytis cristata and Presbytis melalophos with subperiodic Brugia malayi."

Mak JW, Lam PL, Choong MF, Suresh K

[Acta Trop, 1990]

The leaf-monkeys, Presbytis cristata and Presbytis melalophos, experimentally infected with subperiodic Brugia malayi, have been used for studies on the pathoimmunology of the infection and the screening of potential filaricides during the last 6-8 years, and considerable information on the pattern of microfilaraemia and adult worm recoveries have been obtained. The prepatent periods in 97 P. cristata and 45 P. melalophos, each infected with about 200 infective larvae, were similar, these being approximately 70 and 68 days respectively. Although all infected animals became microfilaraemic, the peak geometric mean count was much higher in P. cristata than in P. melalophos, this being 182.0 and 65.8 per ml blood respectively. Mean adult worm recovery expressed as the percentage of the infective dose was 4.7% and 2.5%, respectively. Most worms were recovered from the sacral nodes/thoracic duct or inguinal lymph nodes in these animals. In view of the higher worm recovery and the higher peak microfilaraemia attained, it is concluded that P. cristata is a better model for the infection than P. melalophos.

Pertel R et al. (1974) Comp Gen Pharmacol "Histamine content of the nematode, Caenorhabditis elegans."

Pertel R, Wilson SH

[Comp Gen Pharmacol, 1974]

1. The histamine contect in axenically grown nematodes was found to be 350 ng. per g. wet weight. 2. Histamine content was determined in extracts from the free-living nematode, Caenorhabditis elegans var. Bristol (strain B1-Pl) by an isotope dilution procedure which obviated error encountered in a conventional fluorescence assay. 3. This is the first report of histamine in the Nematoda.

Mak JW et al. (1990) J Helminthol "Antifilarial activity of intravenous suramin and oral diethylcarbamazine citrate on subperiodic Brugia malayi in the leaf-monkey, Presbytis cristata."

Suresh K, Lam PL, Mak JW, Choong MF

[J Helminthol, 1990]

The known filaricides, suramin and diethylcarbamazine citrate, were tested against subperiodic Brugia malayi infection in the leaf-monkey, Presbytis cristata. As expected, intravenous suramin at 10 mg/kg daily x 5 days or 17 mg/kg weekly x 5 weeks, did not show any microfilaricidal activity, but substantially reduced the recovery of live adult worms to 50.6% and 13.6% of controls respectively. Oral diethylcarbamazine citrate at 6 mg/kg daily x 6 or 10 days reduced final microfilarial counts to 30% of initial counts four weeks post-treatment and adult worm recovery was reduced to 4.5% and 0% of controls respectively. Although the antifilarial activity of these drugs against the infection in this non-human primate model appears to be similar to that seen in man, these results have to be confirmed using larger groups of animals.

Mak JW et al. (1990) Parasitol Res "Experimental infection of the leaf-monkey, Presbytis cristata, with subperiodic Brugia malayi."

Suresh K, Lam PL, Mak JW, Choong MF

[Parasitol Res, 1990]

Presbytis cristata monkeys infected through the inoculation of between 200 and 400 subperiodic Brugia malayi infective larvae (L3) in the right thigh, in both thighs or in the dorsum of the right foot were followed up for varying periods of up to about 8 months after infection. All 148 inoculated animals became patent, with mean prepatent periods being between 66 and 76 days. In animals injected in the thigh, the patterns of microfilaraemia were similar, there being a rapid rise in the geometric mean counts (GMCs) of microfilariae during the first 10-12 weeks of patency, which then plateaued at levels of greater than 1000/ml. Adult worm recovery, expressed as the percentage of the infective dose, was significantly higher in animals injected with 100 L3 in each thigh, being 9.4% as compared with 2.8%-4.8% in other groups. It is therefore recommended that animals should be injected with 100 L3 in each thigh and that the testing of potential filaricides in this model be carried out during the phase of rapid increase in microfilaraemia to ensure that any microfilaricidal effect can easily be detected.

Mak JW et al. (1988) Parasitol Res "Effect of ivermectin against subperiodic Brugia malayi infection in the leaf monkey, Presbytis cristata."

Mak JW, Lam PL, Suresh K, Rain AN

[Parasitol Res, 1988]

Ivermectin at single doses of 0.2-1.0 mg/kg body weight reduced the microfilarial counts of subperiodic Brugia malayi in Presbytis cristata by 59.9%-89.6% of initial counts, 4 weeks after treatment. Adult filaricidal activity was poor, live adult worms being recovered from all animals at autopsy. There was no serious side effect at these doses.

Koyiloth M et al. (2021) Biochim Biophys Acta Biomembr "Cholesterol interaction attenuates scramblase activity of SCRM-1 in the artificial membrane."

Koyiloth M, Gummadi SN

[Biochim Biophys Acta Biomembr, 2021]

Phospholipid (PL) scramblases are single-pass transmembrane protein mediating bidirectional PL translocation. Previously in silico analysis of human PL scramblases, predicted the presence of an uncharacterized cholesterol-binding domain spanning partly in the transmembrane helix as well as in the adjacent extracellular coil. This domain was found to be universally conserved in diverse organisms like Caenorhabditis elegans. In this study, we investigated the saturable cholesterol-binding domain of SCRM-1 using fluorescence sterol binding assay, Stern-Volmer quenching, Forster resonance energy transfer, and CD spectroscopy. We observed high-affinity interaction between cholesterol and SCRM-1. Our results support a previous report, which showed that the cholesterol ordering effect reduced the scramblase activity of hPLSCR1. Considering the presence of a high-affinity binding sequence, we propose that the reduction in activity could partly be due to the cholesterol binding. To validate this, we generated a C-terminal helix (CTH) deletion construct (CTH SCRM-1) and a point mutation in the putative cholesterol-binding domain I273D SCRM-1. Deletion construct greatly reduced cholesterol affinity along with loss of scramblase activity. In contrast to this, I273D SCRM-1 retained scrambling activity in proteoliposomes containing ~30mol% cholesterol but lost sterol binding ability. These results suggest that C-terminal helix is crucial for membrane insertion and in the lipid bilayer the scrambling activity of SCRM-1 is modulated through its interaction with cholesterol.