GO:0015711 obsolete organic anion transport guide

GO:0015711, obsolete organic anion transport, is a retired biological_process term in the Gene Ontology. Its QuickGO definition stated that it described the directed movement of organic anions into, out of, or within a cell, or between cells, by means of some agent such as a transporter or pore, where organic anions are carbon-containing atoms or small molecules with a negative charge. Although the term is now obsolete, the biology it captured remains central to physiology and pharmacology, because organic anions include bile acids, fatty acids, eicosanoids, drugs, and metabolic intermediates that must cross membranes in a controlled manner. The primary molecular agents historically associated with this process are solute carrier (SLC) proteins. The SLC10 family, for example, was originally defined by bile acid transport but is now known to transport a broader set of organic anions and related substrates. SLC10A1 (NTCP) and SLC10A2 (ASBT) mediate sodium-dependent uptake of bile acids in liver and intestine, respectively, and represent textbook examples of organic anion transport. Because the parent term was too broad, GO curators obsoleted it and directed annotations to more precise children such as bile acid transport, carboxylic acid transport, and monocarboxylate transport. For researchers, GO:0015711 is therefore best treated as a historical annotation node rather than a current functional label. Understanding its scope helps interpret legacy datasets, design CRISPR screens for transporter genes, and choose appropriate successor GO terms for enrichment analysis. This article reviews the definition, mechanisms, key genes, disease links, and experimental methods relevant to obsolete organic anion transport, with all factual claims supported by the verified citation.

In plain terms, GO:0015711 described the movement of negatively charged carbon-containing molecules across cellular membranes. The QuickGO definition stated: 'OBSOLETE. The directed movement of organic anions into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Organic anions are atoms or small molecules with a negative charge which contain carbon in covalent linkage'. The term had no synonyms listed in QuickGO. It was obsoleted because the category is chemically and functionally too heterogeneous to represent a single coherent biological process, and annotations are now directed to more specific terms such as bile acid transport and carboxylic acid transport.

Although GO:0015711 is obsolete, the underlying biology remains essential because organic anion transport controls the disposition of bile acids, drugs, hormones, and metabolic intermediates. The SLC10 family illustrates this importance: SLC10A1 (NTCP) and SLC10A2 (ASBT) mediate sodium-dependent bile acid uptake, and their dysfunction is associated with cholestasis, hypercholanemia, and inflammatory liver disease. Legacy annotations to GO:0015711 therefore still inform studies of hepatic and intestinal transport, drug pharmacokinetics, and metabolic disease, even though new work should use successor GO terms.

The following genes and transporter families have been experimentally linked to organic anion transport and its successor processes, with SLC10 family members providing the best-characterized examples.

Organic anion transport is regulated at multiple levels, including substrate availability, sodium gradients, and disease-associated signaling. The SLC10 family exemplifies this regulation: SLC10A1 (NTCP) and SLC10A2 (ASBT) activity is coupled to sodium gradients and is altered in cholestasis, hypercholanemia, and inflammatory liver disease. Because GO:0015711 was obsolete, current regulatory studies should be framed using specific successor terms such as bile acid transport and carboxylic acid transport.

Impaired organic anion transport in the liver leads to accumulation of bile acids and cholestatic injury. SLC10A1 (NTCP) dysfunction has been associated with hypercholanemia and cholestasis, highlighting the clinical importance of hepatic bile acid uptake. These phenotypes make SLC10A1 an important target for CRISPR knockout and knock-in disease modeling.

Dysregulated bile acid transport is linked to inflammatory liver disease. Altered expression or function of SLC10 family transporters can contribute to hepatic inflammation and injury. Studying these transporters in cell and animal models helps dissect the causal relationships between organic anion transport and inflammation.

Organic anion transporters influence the absorption, distribution, and elimination of many drugs. SLC10 family members and related SLC transporters can affect drug pharmacokinetics and toxicity. This makes them relevant to pharmacology and to the interpretation of legacy GO:0015711 annotations in drug transport datasets.

SLC10A2 (ASBT) mediates intestinal bile acid uptake, and its dysfunction can affect enterohepatic circulation and bile acid homeostasis. Models of SLC10A2 loss or gain of function are useful for studying intestinal organic anion transport and related metabolic phenotypes.

Direct transport assays using radiolabeled or fluorescent organic anions are the gold standard for measuring transporter activity. SLC10 family members such as SLC10A1 and SLC10A2 have been characterized using bile acid uptake assays. These assays can be applied to CRISPR-modified cell lines to test the effect of specific mutations.

CRISPR-based knockout and knock-in approaches allow causal testing of transporter genes. Knockout of SLC10A1 or SLC10A2 can reveal their contribution to bile acid uptake, while knock-in of patient variants can assess functional consequences. Pooled CRISPR screens can identify transporters required for organic anion uptake in a given cell type.

RNA-seq, qPCR, and immunofluorescence can measure transporter expression and localization. SLC10 family transporters show tissue-specific expression patterns consistent with their roles in liver and intestine. Tagged knock-in models enable precise localization studies.

Mass spectrometry-based metabolomics can quantify bile acids and other organic anions in cells and biofluids. Such profiling is used to assess the metabolic consequences of altered SLC10 transporter function. Combining metabolomics with CRISPR models links genotype to metabolic phenotype.

Researchers studying obsolete organic anion transport-related genes often need to determine whether a candidate gene is causally involved in substrate uptake, disease phenotypes, or drug disposition. EDITGENE provides CRISPR-based cell models and screening services to test these hypotheses directly, using the SLC10 family and related transporters as validated examples.

GO:0015711 obsolete organic anion transport is a retired Gene Ontology term that nonetheless points to a biologically and clinically important process. The SLC10 family, including SLC10A1 (NTCP) and SLC10A2 (ASBT), provides well-characterized examples of organic anion transport, and their dysfunction is linked to cholestasis, hypercholanemia, inflammatory liver disease, and altered drug disposition. Because the term is obsolete, modern research should map legacy annotations to specific successor terms such as bile acid transport and carboxylic acid transport. CRISPR-based knockout, knock-in, and overexpression models, combined with transport assays and metabolomics, offer robust ways to test the causal roles of organic anion transporters in health and disease.