Marko Nykanen

Proficiency of filamentous fungi for producing massive quantities of extracellular enzymes has promoted them attractive resources to be exploited in industrial manufacture of foreign proteins. A number of filamentous fungi are generally regarded as safe to be used, for example, in the food and feed industry. Numerous production bottlenecks are still a mystery, and overall production amounts of foreign proteins are still considerably lower than those obtained for native proteins. The less known attributes in protein production and secretion in filamentous fungi are discussed in the book, where the economically important fungus, Trichoderma reesei, occurs on the spotlight. The fungus has been exploited in food, animal feed, textile and pulp and paper industries, in biological control of plant disease, biodegradation of chlorophenolic compounds, and soil bioremediation. It has been harnessed also in production of calf chymosin and barley cysteine peptidase. Their production and secretory bottlenecks in the fungus are going to be revealed. Could we be able to get the fungus to manufacture effectively also therapeutic proteins in pharmaceutical industry?

Background: The so-called antikeratin antibody (AKA) and the antiperinuclear factor (APF) that recognize proteins related to human epidermal filaggrin belong to the most specific serological markers of rheumatoid arthritis (RA). However, assays for the detection of AKA and APF are currently based on immunofluorescence, a method that is subject to arbitrary interpretation and inadequate standardization of the substrates. Methods: Proteins extracted from human epidermis were separated by reversed-phase high-performance liquid chromatography (HPLC). Filaggrin-containing fractions, identified in immunoblotting by monoclonal antifilaggrin antibodies, were then subjected to gel filtration HPLC and, finally, to a second reversed-phase HPLC step. Tryptic digestion, amino acid sequencing and mass spectrometry were used to cornfirm the identity of the purified protein. Filaggrin was used as antigen in enzyme-linked immunosorbent assay (ELISA) to measure IgG class antifilaggrin antibodies. Res...

Description Tracking the progress of proteins through the secretory pathway requires reliable markers for cell organelles participating in secretion. Endoplasmic reticulum (ER) is the cytoplasmic organelle where the early steps of the protein secretory pathway are ...

We have systematically analysed the ultrastructure of the early secretory pathway in the Trichoderma reesei hyphae in the wild-type QM6a, cellulase-overexpressing Rut-C30 strain and a Rut-C30 transformant BV47 overexpressing a recombinant BiP1-VenusYFP fusion protein with an endoplasmic reticulum (ER) retention signal. The hyphae were studied after 24 h of growth using transmission electron microscopy, confocal microscopy and quantitative stereological techniques. All three strains exhibited different spatial organisation of the ER at 24 h in both a cellulase-inducing medium and a minimal medium containing glycerol as a carbon source (non-cellulase-inducing medium). The wild-type displayed a number of ER subdomains including parallel tubular/cisternal ER, ER whorls, ER-isolation membrane complexes with abundant autophagy vacuoles and dense bodies. Rut-C30 and its transformant BV47 overexpressing the BiP1-VenusYFP fusion protein also contained parallel tubular/cisternal ER, but no ER...

Maturation of barley cysteine endopeptidase B (EPB) in Trichoderma reesei was studied with metabolic inhibitors, Western blotting, and immuno microscopy. The inactive 42-kDa recombinant EPB proprotein, first detected in apical cells, was sequentially processed in a time-dependent manner to a secreted polypeptide of 38.5 kDa, and thereafter, to polypeptides of 37.5, 35.5, and 32 kDa exhibiting enzyme activity both in the hyphae and culture medium. The sizes of the different forms of recombinant EPB were in accordance with molecular masses calculated from the deduced amino acid sequence, assuming cleavage at four putative Kex2p sites present in the 42-kDa proprotein. Both the liquid and the zymogram in-gel activity assays indicated that the 32-kDa enzyme produced in T. reesei in vivo was 2 kDa larger and four times less active than the endogenous EPB. Brefeldin A treatment prevented the last Kex2p processing step of EPB from a 35.5- to a 32-kDa protein. This coincided with a significa...

Hydrocephalus is a pathological accumulation of cerebrospinal fluid (CSF) in the cerebral ventricles that constitutes a significant cause of neurological morbidity and mortality. Surgical treatment involving shunt placement is associated with a high failure rate and complications due to infection, motivating the development of alternative, non-surgical therapies. Here, we investigated the role in hydrocephalus of water channel aquaporin-1 (AQP1), which