Membrane Transport

Squaraine probes for the bimodal staining of lipid droplets and endoplasmic reticulum imaging in live cells

“…This staining pattern regardless of the incubation temperature and cellular state strongly confirms that the bimodal uptake of SQR22 into LDs followed by the ER is through passive transport via the simple diffusion of small molecules and not by active transport mechanisms (endocytosis), which is a temperature-dependent mechanism. 48–51…”

Understanding Mechanisms of Secondary Active Transport by Analyzing the Effects of Mutations and Stoichiometry

“…These cells are surrounded by membranes that provide an effective protection for processing and regulating the fundamental genetic processes. , At the same time, the nonequilibrium nature of biological systems requires that some materials be transported in and out of cells by crossing the membranes . For example, this is needed for sending biological signals, for supplying nutrients, and for removal of waste molecules. − In most cases, this requires an energy input because the involved molecules are large (e.g., sugars, nucleotides, or amino acids), and frequently they must be translocated against their established transmembrane gradients. , …”

Molecular Mechanisms of Active Transport in Antiporters: Kinetic Constraints and Efficiency

“…Biological cells are complex dynamic systems that constantly require the transportation of various species across the cellular membranes for their long-term survival. , For example, necessary nutrients should be moved into the cell, while waste products must be promptly removed out of the cell. − There are several classes of protein membrane channels, generally called transporters, that are devoted to these tasks. ,,− It is often necessary to move species across the membranes against the already established gradients of their concentrations, and this clearly requires the input of energy. Nature came out with a very elegant solution of this problem: multiple classes of membrane channels use the transport of one kind of molecule along its own concentration gradient to drive the motion of another kind of molecule against its concentration gradient.…”

“…Nature came out with a very elegant solution of this problem: multiple classes of membrane channels use the transport of one kind of molecule along its own concentration gradient to drive the motion of another kind of molecule against its concentration gradient. This category of membrane translocations is called secondary active transport or cotransport. ,,, …”

“…Those where particles of both species move in the same direction are labeled as symporters, − while those where the transport of both species is happening in the opposite direction are labeled as antiporters. ,, These membrane channels have been studied using a variety of biochemical and biophysical methods . However, the molecular mechanisms of their process still remain not fully understood. ,,, In this Letter, we would like to concentrate on the microscopic origins of secondary active transport in antiporters.…”