Simultaneous quantification of polysorbate 20 and poloxamer 188 in biopharmaceutical formulations using evaporative light scattering detection.

Polysorbates and Poloxamer 188 constitute the most common surfactants used in biopharmaceutical formulations owing to their excellent protein-stabilizing properties and good safety profiles. In recent years, however, a vast number of reports concerning potential risk factors closely related with their applications, such as the accumulation of degradation products, their inherent heterogeneity and adsorption effects of proteins at silicon/oil interfaces have drawn the focus to potential alternatives. Apart from tedious efforts to evaluate new excipient candidates, the use of mixed formulations leveraging combinations of well-established surfactants appears to be a promising approach to eliminate or, at least, minimize and postpone adverse effects associated with the single compounds.

Biochemical isolation of Argonaute protein complexes by Ago-APP.

During microRNA (miRNA)-guided gene silencing, Argonaute (Ago) proteins interact with a member of the TNRC6/GW protein family. Here we used a short GW protein-derived peptide fused to GST and demonstrate that it binds to Ago proteins with high affinity. This allows for the simultaneous isolation of all Ago protein complexes expressed in diverse species to identify associated proteins, small RNAs, or target mRNAs.

Importin-β facilitates nuclear import of human GW proteins and balances cytoplasmic gene silencing protein levels.

MicroRNAs (miRNAs) guide Argonaute (Ago) proteins to distinct target mRNAs leading to translational repression and mRNA decay. Ago proteins interact with a member of the GW protein family, referred to as TNRC6A-C in mammals, which coordinate downstream gene-silencing processes. The cytoplasmic functions of TNRC6 and Ago proteins are reasonably well established.

Structural features of Argonaute-GW182 protein interactions.

MicroRNAs (miRNAs) guide Argonaute (Ago) proteins to target mRNAs, leading to gene silencing. However, Ago proteins are not the actual mediators of gene silencing but interact with a member of the GW182 protein family (also known as GW proteins), which coordinates all downstream steps in gene silencing. GW proteins contain an N-terminal Ago-binding domain that is characterized by multiple GW repeats and a C-terminal silencing domain with several globular domains.

Argonaute and GW182 proteins: an effective alliance in gene silencing.

Argonaute proteins interact with small RNAs and facilitate small RNA-guided gene-silencing processes. Small RNAs guide Argonaute proteins to distinct target sites on mRNAs where Argonaute proteins interact with members of the GW182 protein family (also known as GW proteins). In subsequent steps, GW182 proteins mediate the downstream steps of gene silencing.

Turning catalytically inactive human Argonaute proteins into active slicer enzymes.

Argonaute proteins interact with small RNAs that guide them to complementary target RNAs, thus leading to inhibition of gene expression. Some but not all Argonaute proteins are endonucleases and can cleave the complementary target RNA. Here, we have mutated inactive human Ago1 and Ago3 and generated catalytic Argonaute proteins.