Tracking labelled protein ends in living cells revealed a relatively sparse centre and protein-rich peripheral regions in nuclear pores. Small passive probes and receptor-carried cargo favoured different paths. The peer-reviewed experiment combines reconstructed three-dimensional distributions with an independent measurement check, while describing time-averaged positions in one cultured cell type.
Molecules travelling between the cell nucleus and cytoplasm encounter a spatially organised barrier, according to a single peer-reviewed live-cell experiment. The researchers mapped 11 proteins called FG nucleoporins in cultured HeLa cells. Their flexible regions contain phenylalanine–glycine repeats and help regulate which molecules pass through nuclear pores.[1]
Fluorescent labels near the protein ends supplied two-dimensional single-molecule positions. Using pore geometry, the researchers reconstructed three-dimensional probability distributions. Independent three-dimensional MINFLUX microscopy checked the annular organisation of the central Nup62 complex. That check addressed the possibility of a reconstruction artifact for these central proteins; it did not independently remap every protein.[1]
A peripheral ring contained contributions from five proteins anchored centrally, while six asymmetrically placed proteins extended beyond the pore’s faces. Nup98 overlapped several regions. The maps describe where labelled ends tend to spend time, leaving the complete paths of flexible protein chains unresolved. Tagging and transient protein expression may also have subtle effects.[1]
In the same cell system, small passively diffusing probes favoured the relatively sparse centre. Receptor-mediated transport followed protein-rich peripheral paths. The authors combine the spatial and transport observations into a three-region framework. The cell experiments were confined to HeLa cultures maintained under standard conditions, so equivalent organisation in other tissues or stressed cells remains to be established.[1]
