A functional family of fluorescent nucleotide analogues to investigate actin dynamics and energetics.

Actin polymerization provides force for vital processes of the eukaryotic cell, but our understanding of actin dynamics and energetics remains limited due to the lack of high-quality probes. Most current probes affect dynamics of actin or its interactions with actin-binding proteins (ABPs), and cannot track the bound nucleotide. Here, we identify a family of highly sensitive fluorescent nucleotide analogues structurally compatible with actin.

Sizes of actin networks sharing a common environment are determined by the relative rates of assembly.

Within the cytoplasm of a single cell, several actin networks can coexist with distinct sizes, geometries, and protein compositions. These actin networks assemble in competition for a limited pool of proteins present in a common cellular environment. To predict how two distinct networks of actin filaments control this balance, the simultaneous assembly of actin-related protein 2/3 (Arp2/3)-branched networks and formin-linear networks of actin filaments around polystyrene microbeads was investigated with a range of actin accessory proteins (profilin, capping protein, actin-depolymerizing factor [ADF]/cofilin, and tropomyosin).

The polyplex, protein corona, cell interplay: Tips and drawbacks.

Polyplexes (PX) are soft materials, obtained by blending polycations and nucleic acids, designed for gene delivery applications. While much is known about the transfection properties of PX, their protein corona, the biomolecules interacting with colloids once in a biological environment, represents an underlooked parameter in gene transfection. In this study, linear and branched polyethylenimines (lPEI and bPEI), the golden standard among non-viral vectors, were selected and used throughout the work: their physicochemical properties and protein corona when complexed to DNA were studied and linked to the toxicity and transfection efficiency arisen upon their delivery to cells.