Hjv is expressed in hepatocyte sinusoidal membranes adjacent to Bmp6-producing SECs. (A) Immunofluorescence microscopy of liver tissue from Rosa26^tdT;Tek-Cre+ mice. Liver SECs are labeled with tdT (red). Hjv expression is visualized with anti-Hjv antibody (green). Nuclei are labeled with DAPI (blue). Scale bar represents 10 μM. Right panel shows boxed area enlarged ×3. (B) Proposed model: BMP6 is produced in liver SECs and acts in a paracrine fashion on hepatocytes to bind the co-receptor HJV, which together with BMP type I and type II receptors induces SMAD1/5/8 phosphorylation and hepcidin transcription.