Ion Carriers and Receptors
The cell is enclosed by a plasma membrane impermeable to many lifesustaining substances. The cell membrane thus incorporates rafts, calveolae, adaptors, transporters, etc. The cell membrane being a major barrier to ion flux, proteic ion carriers, such as ion channels, transporters, exchangers, and pumps, transport ions across it. Besides, signal transduction relies on plasmalemmal receptors and ion carriers.
The motion of ions across cell membranes ensures various physiological processes, such as hormone secretion, action-potential generation, muscle contraction, regulation of blood pressure, salt and water balance, cell proliferation and apoptosis. Moreover, differences in ion concentrations or electrical potential between both sides of the plasmalemma, created by proteic ion carriers produce electrical signals in excitable cells. Changes in membrane polarization occur when ion channels open. The opening and closing of ion channels can be disturbed by gene mutations, leading to alterations in ion conductance through the central pore and possible ion leakage (channelopathies).
KeywordsEpidermal Growth Factor Receptor Vascular Smooth Muscle Cell Tissue Factor Transient Receptor Potential KATP Channel
Unable to display preview. Download preview PDF.