Transporterproteiinit

Transporterproteiinit refer to a large family of membrane-bound proteins that facilitate the movement of various molecules across cellular membranes. These proteins are essential for maintaining cellular homeostasis, regulating transport of ions, nutrients, metabolites, and signaling molecules, and for cellular defense and detoxification. They are categorized according to their molecular structure and energy source into primary and secondary transporters. Primary transporters are powered directly by ATP hydrolysis, the most prominent being the ATP-binding cassette (ABC) transporters. Secondary transporters rely on electrochemical gradients created by other transport activities, including solute carrier (SLC) family proteins. Another class, the ion channels, form pores that allow passive movement of specific ions.

Transporterproteiinit are modular in design. ABC transporters consist of two transmembrane helices forming a pore and two cytosolic nucleotide‑binding domains that hydrolyze ATP to drive conformational changes. SLCs usually harbour multiple transmembrane helices arranged to form a substrate-binding pocket. Many transporter proteins share homologous motifs enabling recognition of particular substrates. They are widespread in prokaryotes, eukaryotes, and mitochondria, reflecting their fundamental role in physiology. In medicine, transporter proteins have become targets for drug delivery, as their substrate specificity can be exploited for oral bioavailability, and they are implicated in multidrug resistance in cancer.

The study of transporterproteiinit involves structural biology, electrophysiology, and genomics. High‑resolution crystal and cryo‑EM structures have illuminated mechanisms of gating, substrate recognition, and ATP hydrolysis. In addition to their physiological roles, transporter proteins are used in biotechnology for bioremediation and biosensing and are essential in synthetic biology to rebuild cellular transport networks.