Gamma-interferon-induced nerve growth factor receptors in colorectal carcinoma cell lines

Identification of the cell surface and nuclear receptors for NGF in a breast carcinoma cell line

125I-nerve growth factor (NGF) was found to be internalized and translocated to the nucleus of SKBr5 breast carcinoma cells. The cytoplasm and chromatin isolated from nonmitotic cells accumulated two- and five-fold, respectively, more of 125I-NGF than the cells undergoing mitosis. MAb 20.4 developed against the NGF cell surface receptor immunoprecipitated the 80,000 M(r) receptor from plasma membrane and two protein species from the chromatin; 90,000 M(r) (major band) and 200,000 M(r) (minor band). In SKBr5 cells, binding of NGF to the chromatin did not affect synthesis of rRNA. Proliferation of SKBr5 cells was slightly stimulated by NGF. In control melanoma A875 cells, which express the 230,000 M(r) chromatin receptor, NGF inhibited both rRNA synthesis and cell proliferation. We suggest that the 90,000 M(r) chromatin receptor expressed by SKBr5 cells represents a "nonactive," ligand-binding subunit of the high molecular weight receptor for NGF. The critical role of the chromatin receptor for NGF in rRNA-dependent cell proliferation is discussed.