Cloning and characterization of T-cell lymphoma invasion and metastasis 2 (TIAM2), a novel guanine nucleotide exchange factor related to TIAM1

TIAM1 is a guanine nucleotide exchange factor that was identified in a scre en for genes that increase the invasiveness of T lymphoma cell Lines (Habet s et ab, 1994, Cell 77(4): 537-549). We have identified a gene, T-cell lymp homa invasion and metastasis 2 (HGMW-approved symbol TIAM2), with significa nt identity to the carboxyl-terminal region of the TIAM1 and mapped it to 6 q25. TIAM2 is expressed as an similar to 3.3-kb transcript in cerebrum and as an similar to 4.4-kb transcript in the cerebellum and testis. The simila r to 4.4-kb message encodes a longer form of the similar to 3.3-kb mRNA pre dicted protein, and both contain homology to the Dbl-homologous region (70% ) and Pleckstrin-homologous (54%) regions of TIAM1. We have purified TIAM2 and shown it to have GDP-GTP exchange activity. In situ hybridizations demo nstrate TIAM2 expression in the E13.5 telencephalon of mouse embryos and in the cerebral cortex, hippocampus, and ependyma of adult mouse brains. (C) 1999 Academic Press.