Pip92: a short-lived, growth factor-inducible protein in BALB/c 3T3 and PC12 cells

pip92 is a cellular immediate-early gene inducible by serum growth factors in fibroblasts. It is also induced in the rat pheochromocytoma cell line PC12 by agents that cause proliferation, neuronal differentiation, and membrane depolarization. We show that the pip92-encoded polypeptide is a proline-rich protein of 221 amino acids, has an extremely short half-life, and is localized in the cytoplasm. We hypothesize that Pip92 plays a role in mediating the cellular responses to a variety of extracellular signals.