Carriers are proteins or molecules that transport specific substances, such as ions, nutrients, or signaling molecules, across cell membranes or within cells. These carriers play a crucial role in maintaining cellular homeostasis and facilitating various physiological processes, such as nutrient uptake, hormone signaling, and neurotransmission. Research in carrier biology focuses on understanding the structure, function, and regulation of these transport proteins and their roles in health and disease. Studies in this area often involve identifying new carriers, characterizing their substrate specificity, investigating their mechanisms of action, and exploring their potential as therapeutic targets for various medical conditions.