Pelisch F et al. (2016) Mol Cell "A SUMO-Dependent Protein Network Regulates Chromosome Congression during Oocyte Meiosis."

Jaffray EG, Gartner A, Wang B, Hay RT, Tammsalu T, Pelisch F

[Mol Cell, 2016]

During Caenorhabditis elegans oocyte meiosis, a multi-protein ring complex (RC) localized between homologous chromosomes, promotes chromosome congression through the action of the chromokinesin KLP-19. While some RC components are known, the mechanism of RC assembly has remained obscure. We show that SUMO E3 ligase GEI-17/PIAS is required for KLP-19 recruitment to the RC, and proteomic analysis identified KLP-19 as a SUMO substrate invivo. Invitro analysis revealed that KLP-19 is efficiently sumoylated in a GEI-17-dependent manner, while GEI-17 undergoes extensive auto-sumoylation. GEI-17 and another RC component, the kinase BUB-1, contain functional SUMO interaction motifs (SIMs), allowing them to recruit SUMO modified proteins, including KLP-19, into the RC. Thus, dynamic SUMO modification and the presence of SIMs in RC components generate a SUMO-SIM network that facilitates assembly of the RC. Our results highlight the importance of SUMO-SIM networks in regulating the assembly of dynamic protein complexes.

Surana P et al. (2017) PLoS One "Structural and functional analysis of SMO-1, the SUMO homolog in Caenorhabditis elegans."

Surana P, Tripathi V, Broday L, Das R, Gowda CM

[PLoS One, 2017]

SUMO proteins are important post-translational modifiers involved in multiple cellular pathways in eukaryotes, especially during the different developmental stages in multicellular organisms. The nematode C. elegans is a well known model system for studying metazoan development and has a single SUMO homolog, SMO-1. Interestingly, SMO-1 modification is linked to embryogenesis and development in the nematode. However, high-resolution information about SMO-1 and the mechanism of its conjugation is lacking. In this work, we report the high-resolution three dimensional structure of SMO-1 solved by NMR spectroscopy. SMO-1 has flexible N-terminal and C-terminal tails on either side of a rigid beta-grasp folded core. While the sequence of SMO-1 is more similar to SUMO1, the electrostatic surface features of SMO-1 resemble more with SUMO2/3. SMO-1 can bind to typical SUMO Interacting Motifs (SIMs). SMO-1 can also conjugate to a typical SUMOylation consensus site as well as to its natural substrate HMR-1. Poly-SMO-1 chains were observed in-vitro even though SMO-1 lacks any consensus SUMOylation site. Typical deSUMOylation enzymes like Senp2 can cleave the poly-SMO-1 chains. Despite being a single gene, the SMO-1 structure allows it to function in a large repertoire of signaling pathways involving SUMO in C. elegans. Structural and functional features of SMO-1 studies described here will be useful to understand its role in development.

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."

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

[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.

Garms R (1987) Trop Med Parasitol "Infection rates and parasitic loads of Onchocerca volvulus, and other filariae, in Simulium sanctipauli s.l. and S. yahense in a rain-forest area of Liberia."

Garms R

[Trop Med Parasitol, 1987]

Simulium sanctipauli s.l. and S. yahense are common and widespread in the rain-forest zone of Liberia, but differ with regard to their biting densities and contribution to the transmission of Onchocerca volvulus. Although, in a study area on the St. Pauli River, S. sanctipauli s.l. (presumably S. soubrense in the sense of Post) was the predominant ma-biting species (74.3% of 30,855 females examined), S. yahense was shown to be the important vector. While 1000 biting females of S. yahense carried 96 3rd stage larvae indistinguishable from O. volvulus, only 14 were found per 1000 females of S. sanctipauli s.l. Of the parous females (3135 S. sanctipauli s.l./1621 S. yahense) 23.8/39.9% harboured 1st and/or 2nd stage filarial larvae and 1.9/9.4% 3rd stage larvae of O. volvulus. Animal filariae of unknown origin, indicative of zoophily, were very common in S. sanctipauli s.l. (13.8%) but practically absent from S. yahense (0.5%). In spite of its poorer vectorial performance S. sanctipauli s.l. cannot be neglected as a vector because it may occur in high biting densities and contribute considerably to the transmission, in particular in the vicinity of the St. Paul River. The interplay of two vector species, which develop in different types of water-courses explains the overall high endemicity of onchocerciasis in the study area.

Schwarzbauer JE et al. (1994) Methods Enzymol "Extracellular calcium-binding protein SPARC/osteonectin in Caenorhabditis elegans."

Ryan CS, Mussetbi F, Schwarzbauer JE

[Methods Enzymol, 1994]

The nematode Caenorhabditis elegans is an excellent genetic system for dissecting protein function. Beginning with the pioneering work of Brenner numerous mutations have been generated and characterized phenotypically. Ease of culture, transparency, and small size, (fewer than 1000 nongonadal nuclei), have allowed the determination of a complete cell lineage map by direct observation of living nematodes. Colocalizatioin of genetic and physical loci is made possible by an extensive C. elegans genome map. The ability to identify genes corresponding to particular mutations has ad significantly with the development of methods for transformation of mutants with wild-type genes. The ability to introduce mutations into specific genes is now becoming possible by Tc1 transposon insertion of excision. A comprehensive volume describing all aspects of nematode biology is an excellent resource for anyone studying C. elegans, from novice to expert. In addition, The Worm Breeder's Gazette, published quarterly by the Caenorhabditis Genetics Center (CGC, University of Minnesota, St. Paul, MN), contains short research articles and technical notes contributed by members of the nematode community and represents a unique mechanism for keeping abreast of the latest techniques and the most recent results from other laboratories. The CGC, supported by the NIH National Center for Research Resources, also maintains a large collection of normal and mutant strains for distribution on request.

Hanneman AJ et al. (2006) Glycobiology "Isomer and glycomer complexities of core GlcNAcs in Caenorhabditis elegans."

Rosa JC, Ashline D, Hanneman AJ, Reinhold VN

[Glycobiology, 2006]

Analysis of protein glycosylation within the nematode Caenorhabditis elegans has revealed an abundant and unreported set of core chitobiose modifications (CCM) to N-linked glycans. With hydrazine release an array of glycomers and isobars were detected with hexose extensions on the 3- and 3,6-positions of the penultimate and reducing terminus, respectively. A full complement of structures includes a range of glycomers posessing a Galss(1-4)Fuc disaccharide at the 3- and 6-positions of the protein-linked GlcNAc. Importantly, enzymatic (PNGase F/A) release failed to liberate many of these extended structures from reduced and alkylated peptides and, as a consequence, such profiles were markedly deficient in a representation of the worm glycome. Moreover, the 3-linked Galss(1-4)Fuc moiety was notably resistant to a range of commercial galactosidases. For identification the fragments were spectrum-matched with synthetic products and library standards using sequential mass spectrometry (MS(n)). A disaccharide observed at the 3-position of penultimate GlcNAc, indicating a Hex-Fuc branch on some structures, was not further characterized due to low ion abundance in MS(n). Additionally, a Hex-Hex-Fuc trisaccharide on the 6-position of proximal GlcNAc was also distinguished on select glycomers. Similar branch extensions on 6-linked core fucosyl residues have recently been reported among other invertebrates. Natural methylation and numerous isobars complement the glycome, which totals well over 100 individual structures. Complex glycans were detected at lower abundance, indicating glucosaminyltransferase (GnT)-I and GnT-II activity. A range of phosphorylcholine (PC) substituted complex glycans was also confirmed following a signature two-stage loss of PC during MS(n) analysis, although the precursor ion was not observed in the mass profiles. In a similar manner numerous other minor glycans may be present but unobserved in hydrazine release profiles dominated by fucosylated structures. All CCM structures, including multiple isomers, were determined without chromatography by gas-phase disassembly, (MS(n)), in Paul and linear ion trap instruments.