Non-specific endocytosis

Non-specific endocytosis, which includes processes such as pinocytosis and macropinocytosis, is a fundamental cellular mechanism for the internalization of extracellular fluid and dissolved solutes through the invagination of the plasma membrane (Conner & Schmid, Nature, 2003). Unlike receptor-mediated endocytosis, this pathway does not rely on the binding of specific ligands to surface receptors, allowing for the bulk uptake of various substances (Alberts et al., Molecular Biology of the Cell). In pharmacology, this process is a primary route for the cellular entry of non-targeted delivery systems, such as certain nanoparticles, liposomes, and oligonucleotides (Sahay et al., Journal of Controlled Release, 2010). While it enables the delivery of large molecules that cannot passively diffuse across the membrane, the lack of specificity often results in broad tissue distribution and potential off-target effects. Furthermore, cancer cells frequently exploit macropinocytosis to scavenge extracellular proteins as a nutrient source to support rapid proliferation (Commisso et al., Nature, 2013). Additionally, various pathogens, including certain viruses and bacteria, utilize these non-specific pathways to bypass the cell membrane and initiate infection (Mercer & Helenius, Nature Cell Biology, 2009).

Other names

PinocytosisFluid-phase endocytosisMacropinocytosisBulk-phase endocytosis

Internalization of extracellular fluid and solutes via plasma membrane invagination and vesicle formation independent of specific ligand-receptor binding (Conner & Schmid, Nature, 2003).