In
cellular biology,
membrane transport refers to the collection of mechanisms that regulate the passage of
solutes such as
ions and small
molecules through
biological membranes, which are
lipid bilayers that contain
proteins embedded in them. The regulation of passage through the membrane is due to selective membrane permeability - a characteristic of biological membranes which allows them to separate substances of distinct chemical nature. In other words, they can be permeable to certain substances but not to others.
The movements of most solutes through the membrane are mediated by
membrane transport proteins which are specialized to varying degrees in the transport of specific molecules. As the diversity and
physiology of the distinct
cells is highly related to their capacities to attract different external elements, it is postulated that there is a group of specific transport proteins for each cell type and for every specific physiological stage
[1]. This differential expression is
regulated through the differential
transcription of the
genes coding for these proteins and its translation, for instance, through genetic-molecular mechanisms, but also at the cell biology level: the production of these proteins can be activated by
cellular signaling pathways, at the
biochemical level, or even by being situated in
cytoplasmic vesicles.