An apparently reliable antibody for phosphorylated SMAD 1 and 5 detection on mouse and rat liver homogenate, used for example by Léon Kautz in the famous 2014 erythroferrone paper. Gives very specific bands:

Used by our group for the detection of phosphorylated SMADs 1 and 5 in our last SMAD paper, gives satisfactory results:

Frýdlová J, Rogalsky DW, Truksa J, Nečas E, Vokurka M, Krijt J. Effect of stimulated erythropoiesis on liver SMAD signaling pathway in iron-overloaded and iron-deficient mice. PLoS One. 2019;14(4):e0215028.