We have been studying tumor cell motility as a component of the process of metastatic dissemination. A number of autocrine motility factors (AMF's) have been shown to be synthesized by human tumor cells. These AMF's stimulate both directed and random motility in the same cells that produce the factor. Recently we purified a novel AMF which we termed autotaxin (ATX). Homogeneously purified ATX was enzymatically digested and the resulting peptides were purified by reverse phase HPLC. Thirty of these peptides were sequenced by Edman degradation. An expression library was screened with anti-peptide antibodies to obtain a partial clone containing the 3'end of the ATX cDNA. This clone was then extended utilizing reverse transcriptase/polymerase chain reaction and 5' RACE techniques. The full-length cDNA clone is 3251 bp long with an open-reading frame that encodes a 915 amino acid polypeptide. This deduced polypeptide sequence matches all 30 of the previously sequenced peptides. A second autotaxin-like molecule was cloned from the human teratacarcinoma cell line, N-tera 2D1. This full-length clone has been utilized to produce recombinant ATX (rATX). Both A2058 and recombinant ATX stimulate motility, exhibit type I phosphodiesterase activity, bind to ATP, and autophosphorylate/dephosphorylate. However, A2058 ATX has 30-50 fold more autokinase activity than rATX.
