Species predicted to react based on 100% sequence homology:Mouse, Rat
Specificity / Sensitivity
Phospho-ALK (Tyr1078) Antibody detects ALK only when phosphorylated at Tyr1078, which is equivalent to Tyr138 in NPM-ALK. This antibody may also cross-react with other overexpressed tyrosine phosphorylated proteins.
Source / Purification
Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr1078 of human ALK protein. Antibodies are purified by protein A and peptide affinity chromatography.
Background
Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor for pleiotrophin (PTN), a growth factor involved in embryonic brain development (1-3). In ALK-expressing cells, PTN induces phosphorylation of both ALK and the downstream effectors IRS-1, Shc, PLCγ, and PI3 kinase (1). ALK was originally discovered as an NPM (nucleophosmin)-ALK fusion protein produced by a translocation (4). The NPM-ALK fusion protein is a constitutively active, oncogenic tyrosine kinase associated with anaplastic lymphoma (4). Activation of PLCγ by NPM-ALK has been suggested to be a crucial step for its mitogenic activity and may be important in the pathogenesis of anaplastic lymphomas (5). A distinct ALK oncogenic fusion protein involving ALK and EML4 has been described from a non-small cell lung cancer cell line, with corresponding fusion transcripts present in some cases of lung adenocarcinoma. The short, amino-terminal region of the microtubule-associated protein EML4 is fused to the kinase domain of ALK (6,7).Phosphorylation of ALK on Tyr1078 was identified at Cell Signaling Technology (CST) using PhosphoScan®, CST's LC-MS/MS platform for phosphorylation site discovery. Phosphorylation of ALK at Tyr1078 was observed in select carcinoma cell lines and in tumors.