RNA purification from tumor cell protrusions using porous polycarbonate filters.

Actin-rich cellular protrusions or pseudopodia form via local actin filament polymerization and branching and represent a variety of polarized cellular domains including lamellipodia, filipodia, and neuronal growth cones. RNA localization and local protein translation in these domains are important for various cellular processes. RNA transport and local synthesis have been implicated in cell migration and tumor cell metastasis as well as in neuronal plasticity in neurons. Characterization of the mRNAs present in these domains is key to understanding the functional role of mRNA translocation and local protein translation in cellular processes. We describe here a method to segregate pseudopodia of metastatic cancer cells from the cell body using porous polycarbonate filters. This approach enables the purification and identification of RNAs and proteins in these protrusive cellular domains.