"SLC-omics" of the kidney: solute transporters along the nephron.

The fluid in the 14 distinct segments of the renal tubule undergoes sequential transport processes that gradually convert the glomerular filtrate into the final urine. The solute carrier (SLC) family of proteins is responsible for much of the transport of ions and organic molecules along the renal tubule. In addition, some SLC family proteins mediate housekeeping functions by transporting substrates for metabolism. Here, we have developed a curated list of SLC family proteins. We used the list to produce resource webpages that map these proteins and their transcripts to specific segments along the renal tubule. The data were used to highlight some interesting features of expression along the renal tubule including sex-specific expression in the proximal tubule and the role of accessory proteins (ß-subunit proteins) that are thought to be important for polarized targeting in renal tubule epithelia. Also, as an example of application of the data resource, we describe the patterns of acid-base transporter expression along the renal tubule.

The SLC transporter in nutrient and metabolic sensing, regulation, and drug development.

The prevalence of metabolic diseases is growing worldwide. Accumulating evidence suggests that solute carrier (SLC) transporters contribute to the etiology of various metabolic diseases. Consistent with metabolic characteristics, the top five organs in which SLC transporters are highly expressed are the kidney, brain, liver, gut, and heart. We aim to understand the molecular mechanisms of important SLC transporter-mediated physiological processes and their potentials as drug targets. SLC transporters serve as 'metabolic gate' of cells and mediate the transport of a wide range of essential nutrients and metabolites such as glucose, amino acids, vitamins, neurotransmitters, and inorganic/metal ions. Gene-modified animal models have demonstrated that SLC transporters participate in many important physiological functions including nutrient supply, metabolic transformation, energy homeostasis, tissue development, oxidative stress, host defense, and neurological regulation. Furthermore, the human genomic studies have identified that SLC transporters are susceptible or causative genes in various diseases like cancer, metabolic disease, cardiovascular disease, immunological disorders, and neurological dysfunction. Importantly, a number of SLC transporters have been successfully targeted for drug developments. This review will focus on the current understanding of SLCs in regulating physiology, nutrient sensing and uptake, and risk of diseases.

Classification Systems of Secondary Active Transporters.

Membrane-bound solute carrier (SLC) transporter proteins are vital to the human body, as they sustain homeostasis by moving soluble molecule as nutrients, drugs, and waste across lipid membranes. Of the 430 identified secondary active transporters in humans, 30% are still orphans, and systematic research has been requested to elaborate on their possible involvement in diseases and their potential as drug targets. To enable this, the various classification systems in use must be understood and used correctly. In this review, we describe how various classification systems for human SLCs are constructed, and how they overlap and differ. To facilitate communication between researchers and to avoid ambiguities, everyone must clearly state which classification system they are referring to when writing scientific articles.