|Detection of Human and Mouse Metadherin by Western Blot. Western blot shows lysates of P19 mouse embryonal carcinoma cell line and MDA‑MB‑231 human breast cancer cell line. PVDF membrane was probed with 0.25 µg/mL of Sheep Anti-Human/Mouse Metadherin Antigen Affinity-purified Polyclonal Antibody (Catalog # AF7180) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). Specific bands were detected for Metadherin at approximately 80 and 75 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
MTDH (Metadherin; also Lyric and Astrocyte-elevated gene-1/AEG1) is a unique molecule originally discovered to be upregulated in astrocytes following HIV infection. Although its predicted MW is 64 kDa, it runs anomalously at approximately 80 kDa in SDS-Page. It is widely expressed, and appears to be a component of the ER, nucleolus and inner nuclear membrane. MTDH is reported to promote Akt/PI3 kinase activity, and suppress apoptosis-associated FOXO3A transcription. Mouse MTDH is a type III (i.e.- a type I with no signal sequence) transmembrane protein 579 amino acids (aa) in length. It contains a luminal N-terminus (aa 1-48) with a 510 aa cytoplasmic C-terminus. There are no identifiable structural motifs, although two poly-Lys segments and two utilized Ser phosphorylation sites exist. Multiple bands at 80 kDa, 75 kDa, 50-55 kDa and 37 kDa are seen for MTDH on SDS-Page. They may reflect the presence of at least two potential isoform variants that show 1) a deletion of aa 422-457, and 2) an Ile substitution for aa 190-579. Over aa 167-297, mouse MTDH shares 98% and 97% aa sequence identity with rat and human MTDH, respectively.