phospho-SMAD 1,5,9

Cell Signaling Technology  #13820

Disclaimer: The fact that this page reports negative results with the given antibody does not mean that the antibody does not work – it just means that our laboratory did not succeed, using our typical experimental protocol, to find the searched protein by immunoblotting in the tissue examined. Modificiation of the protocol, or the selection of other tissue, might still provide excellent results.


Phosphorylated SMADs are quite important in the regulation of hepcidin expression, which makes them an important target for immunoblotting. Years ago, Cell Signaling Technology produced a reliable antibody for in vivo phospho SMAD 1,5,8 detection, namely #9511. This antibody has been discontinued, and the new monoclonal antibody # 13820 is, at least in our hands (lot 1, reference date 09/2016), not able to detect phospholytad SMADs in mouse or rat liver homogenate. Interestingly, we discussed this disappointing result at the 2017 BioIron conference and found that a high-profile French group came to the same conclusion. Therefore, we recently switched to Abcam ab92698, which gives satisfactory in vivo results. However, it should be noted that the # 13820 antibody is reported to detect phosphorylated SMADs in vitro (Arezes J et al, Erythroferrone inhibits the induction of hepcidin by BMP6, Blood. 2018 Aug 10,  doi:10.1182/blood-2018-06-857995). It therefore seems that this antibody reliably works in vitro, but not in vivo. Alternatively, it is also possible that this antibody works only on nuclear extracts and not on homogenates, since successful use has been recently reported for pSMAD detection in nuclear extracts from mice (Petzer V et al., A fully human anti-BMP6 antibody reduces the need for erythropoietin in rodent models of the Anemia of Chronic Disease. Blood. 2020;  doi:10.1182/blood.2019004653.