The growing need for biologics to be administered subcutaneously and ocularly, coupled with certain indications requiring high doses, has resulted in an increase in drug substance (DS) and drug product (DP) protein concentrations. With this increase, more emphasis must be placed on identifying critical physico-chemical liabilities during drug development, including protein aggregation, precipitation, opalescence, particle formation, and high viscosity. Depending on the molecule, liabilities, and administration route, different formulation strategies can be used to overcome these challenges.
View Article and Find Full Text PDFAnticalin proteins have been proven as versatile clinical stage biotherapeutics. Due to their small size (∼20 kDa), they harbor a short intrinsic plasma half-life which can be extended, e.g.
View Article and Find Full Text PDFNonsense-mediated mRNA decay (NMD) eliminates different classes of mRNA substrates including transcripts with long 3' UTRs. Current models of NMD suggest that the long physical distance between the poly(A) tail and the termination codon reduces the interaction between cytoplasmic poly(A)-binding protein (PABPC1) and the eukaryotic release factor 3a (eRF3a) during translation termination. In the absence of PABPC1 binding, eRF3a recruits the NMD factor UPF1 to the terminating ribosome, triggering mRNA degradation.
View Article and Find Full Text PDFWe established a homogeneous luminescent oxygen channeling sensor for measuring activation states of small GTPases. The assay quantifies activated GTPases in cell lysates, can be applied to different GTPases, and can be used for multiplex screening. The study will provide guidelines for determining activation states of diverse GTPases in various biological contexts.
View Article and Find Full Text PDFSignal recognition particle (SRP)-dependent protein targeting is a universally conserved process that delivers proteins to the bacterial cytoplasmic membrane or to the endoplasmic reticulum membrane in eukaryotes. Crucial during targeting is the transfer of the ribosome-nascent chain complex (RNC) from SRP to the Sec translocon. In eukaryotes, this step is co-ordinated by the SRβ subunit of the SRP receptor (SR), which probably senses a vacant translocon by direct interaction with the translocon.
View Article and Find Full Text PDFEvolutionary retention of duplicated genes encoding transcription-associated proteins (TAPs, comprising transcription factors and other transcriptional regulators) has been hypothesized to be positively correlated with increasing morphological complexity and paleopolyploidizations, especially within the plant kingdom. Here, we present the most comprehensive set of classification rules for TAPs and its application for genome-wide analyses of plants and algae. Using a dated species tree and phylogenetic comparative (PC) analyses, we define the timeline of TAP loss, gain, and expansion among Viridiplantae and find that two major bursts of gain/expansion occurred, coinciding with the water-to-land transition and the radiation of flowering plants.
View Article and Find Full Text PDFBackground: The signal recognition particle (SRP) receptor plays a vital role in co-translational protein targeting, because it connects the soluble SRP-ribosome-nascent chain complex (SRP-RNCs) to the membrane bound Sec translocon. The eukaryotic SRP receptor (SR) is a heterodimeric protein complex, consisting of two unrelated GTPases. The SRbeta subunit is an integral membrane protein, which tethers the SRP-interacting SRalpha subunit permanently to the endoplasmic reticulum membrane.
View Article and Find Full Text PDFThe signal recognition particle (SRP)-dependent cotranslational targeting of proteins to the cytoplasmic membrane in bacteria or the endoplasmic reticulum membrane in eukaryotes is an essential process in most living organisms. Eukaryotic cells have been shown to respond to an impairment of the SRP pathway by (i) repressing ribosome biogenesis, resulting in decreased protein synthesis, and (ii) by increasing the expression of protein quality control mechanisms, such as chaperones and proteases. In the current study, we have analyzed how bacteria like Escherichia coli respond to a gradual depletion of FtsY, the bacterial SRP receptor.
View Article and Find Full Text PDFDifferent from eukaryotes, the bacterial signal recognition particle (SRP) receptor lacks a membrane-tethering SRP receptor (SR) beta subunit and is composed of only the SR alpha homologue FtsY. FtsY is a modular protein composed of three domains. The N- and G-domains of FtsY are highly similar to the corresponding domains of Ffh/SRP54 and SR alpha and constitute the essential core of FtsY.
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