During calcium-regulated exocytosis, the constitutive fusion machinery is 'clamped' in a partially assembled state until synchronously released by calcium. The protein machinery involved in this process is known, but the supra-molecular architecture and underlying mechanisms are unclear. Here, we use cryo-electron tomography analysis in nerve growth factor-differentiated neuro-endocrine (PC12) cells to delineate the organization of the release machinery under the docked vesicles.
View Article and Find Full Text PDFMonoclonal antibody (mAb) therapy has been successfully used for the treatment of B-cell lymphomas and is currently extended for the treatment of multiple myeloma (MM). New developments in MM therapeutics have achieved significant survival gains in patients but the disease still remains incurable. Elotuzumab (HuLuc63), an anti-CS1 monoclonal IgG1 antibody, is believed to induce anti-tumor activity and MM cytotoxicity through antibody dependent cellular cytotoxicity (ADCC) and inhibition of MM cell adhesion to bone marrow stromal cells (BMSCs).
View Article and Find Full Text PDFThe methylotrophic yeast Pichia pastoris is an attractive expression system due to its ability to secrete large amounts of recombinant protein, with the potential for glycosylation. Advances in glycoengineering of P. pastoris have successfully demonstrated the humanization of both the N- and O-linked glycosylation pathways in this organism.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
March 2014
The methylotrophic yeast Pichia pastoris is an attractive expression system for heterologous protein production due to its ability to perform posttranslational modifications, such as glycosylation, and secrete large amounts of recombinant protein. However, the structures of N- and O-linked oligosaccharide chains in yeast differ significantly from those of mammalian cells. The most common O-linked glycan structures added by P.
View Article and Find Full Text PDFYeast are important production platforms for the generation of recombinant proteins. Nonetheless, their use has been restricted in the production of therapeutic proteins due to differences in their glycosylation profile with that of higher eukaryotes. The yeast strain Pichia pastoris is an industrially important organism.
View Article and Find Full Text PDFThe methylotrophic yeast, Pichia pastoris, is an important organism used for the production of therapeutic proteins. Previously, we have reported the glycoengineering of this organism to produce human-like N-linked glycans but up to now no one has addressed engineering the O-linked glycosylation pathway. Typically, O-linked glycans produced by wild-type P.
View Article and Find Full Text PDFPurpose: P. pastoris has previously been genetically engineered to generate strains that are capable of producing mammalian-like glycoforms. Our objective was to investigate the correlation between sialic acid content and pharmacokinetic properties of recombinant TNFR2:Fc fusion proteins generated in glycoengineered P.
View Article and Find Full Text PDFErythropoietin (EPO) is an important molecule in the erythropoiesis and various forms of EPO have been marketed in managing anemia in humans. Long acting EPOs for less frequent dosing have been generated either by increasing the number of glycosylation sites of the EPO molecule or by linking it to a polyethylene glycol (PEG). We have generated recombinant human EPO (rhEPO) using glycoengineered Pichia pastoris strains and evaluated the pharmacokinetics (PK) in rats of this molecule linked to a 40 kDa PEG (PEGylated rhEPO), in relation to its glycosylation patterns.
View Article and Find Full Text PDFThe secretory pathway of the yeast Pichia pastoris has been engineered to produce complex human-type N-glycans (Choi et al., Proc Natl Acad Sci USA 100:5022-5027, 2003; Hamilton et al., Science 301:1244-1246, 2003; Hamilton et al.
View Article and Find Full Text PDFPichia pastoris is a methylotropic yeast that has gained great importance as an organism for protein expression in recent years. Here, we report the expression of recombinant human erythropoietin (rhEPO) in glycoengineered P. pastoris.
View Article and Find Full Text PDFThe methylotrophic yeast, Pichia pastoris, is an important organism used for the production of therapeutic proteins. However, the presence of fungal-like glycans, such as those containing β-mannose (Man) linkages, can elicit an immune response or bind to Man receptors, thus reducing their efficacy. Recent studies have confirmed that P.
View Article and Find Full Text PDFThe N-glycosylation pathway in Pichia pastoris has been humanized by the deletion of genes responsible for fungal-type glycosylation (high mannose) as well as the introduction of heterologous genes capable of forming human-like N-glycosylation. This results in a yeast host that is capable of expressing therapeutic glycoproteins. A thorough investigation was performed to examine whether glycoproteins expressed in glycoengineered P.
View Article and Find Full Text PDFGlycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum amoebae, was postulated previously to play a role in phagocytosis. The gene for gp130 was cloned and when translated, yielded a 768 amino acid preproprotein of 85.3 kDa.
View Article and Find Full Text PDF