Biology of SLC13A5
SLC13A5 (NaCT, INDY) is a sodium-citrate co-transporter that is highly expressed in the liver. It is a member of the SLC13 family of which there are 4 other members. SLC13A5 transports citrate from the circulatory system into hepatocytes where it is used in the synthesis of sterols and fatty acids. SLC13A5 was first identified in Drosophila where the name I’m Not Dead Yet or INDY was coined. A study in 2000(1) showed that lower expression of SLC13A5 in Drosophila led to increased lifespan. Mouse models have demonstrated the potential of this protein as a target for obesity and diabetes with knockout mice protected from adiposity (2), reduced lipid concentrations in a siRNA study (3) and a substrate analogue used to lower blood glucose levels (4). More recently mutations in SLC13A5 have been linked to early-infantile epileptic encephalopathy (5) while silencing of the SLC13A5 gene inhibits proliferation of human hepatocarcinoma cells (6).
BI1383298 is a potent inhibitor of SLC13A5 which unlike previously published inhibitors (4,7) has no structural homology to the substrate (citrate). It is selective over other family members and other transporters. A chemically related negative control (BI01372674) is also provided.
BI01383298: a chemical probe for SLC13A5
In addition to the chemical probe (BI01383298) we also include a negative control (BI01372674) which is chemically analogous to the probe molecule.
The probe molecule (BI01383298) and control (BI01372674) are soluble, after visual inspection, at 10 µM and 200µM in the presence of 0.1% DMSO in media and assay buffer.
Aliquots of stock Solutions were prepared as follows: 10mM BI01383298 in DMSO (Stored -20oC), 5mM BI01383298 in DMSO (Stored -20oC, need agitation upon thaw and gentle warming to 30oC).
SLC13A5 engagement in vitro
BI01383298 but not BI01372674 demonstrates target engagement in vitro with purified human SLC13A5 protein as shown using a thermostabilisation assay with the Prometheus label-free system from Nanotemper (figure 2).
Figure 2: Thermostabilisation of human SLC13A5 by BI01383298 and BI01372674 between 0.1µM and 10µM. SLC13A5 assay concentration of 1µM. Data summarises 3 biological samples with between 4 and 8 replicates for each.