Janus kinase-2 (JAK2) is a non-receptor tyrosine kinase signaling molecule that
mediates the effects of various hormones and cytokines, including interferon, erythropoietin,
leptin, and growth hormone. It also fosters tumor growth and modifies the activity of several
nutrient transporters. JAK2 contributes to the regulation of the cell volume, protectS cells during energy depletion,
proliferation, and aids the survival of tumor cells. Recently, JAK2 was identified as a powerful regulator
of transport processes across the plasma membrane. Either directly or indirectly JAK2 may stimulate or
inhibit transporter proteins, including ion channels, carriers and Na+/K+ pumps. As a powerful regulator of
transport mechanisms across the cell membrane, JAK2 regulates a wide variety of potassium, calcium, sodium
and chloride ion channels, multiple Na+-coupled cellular carriers including EAAT1-4, NaPi-IIa, SGLT1,
BoaT1, PepT1-2, CreaT1, SMIT1, and BGT1 as well as Na+/K+-ATPase. These cellular transport regulations
contribute to various physiological and pathophysiological processes and thus exerting JAK2-sensitive effects.
Future investigations will be important to determine whether JAK2 regulates cell-surface expression of
other transporters and further elucidate underlying mechanisms governing JAK2 actions.