IDENTIFICATION AND CHARACTERIZATION OF RPTP-RHO, A NOVEL RPTP-MU KAPPA-LIKE RECEPTOR PROTEIN-TYROSINE-PHOSPHATASE WHOSE EXPRESSION IS RESTRICTED TO THE CENTRAL-NERVOUS-SYSTEM/

We describe the cloning, chromosomal localization and characterization of RPTP rho, a new member of the RPTP mu/kappa phosphatase subfamily. Receptor tyrosine phosphatases in this subfamily are comprised of a M AM domain near the N-terminal, an immunoglobulin-like domain, four fib ronectin type III repeats, a single transmembrane domain, and a large juxtamembrane segment followed by two intracellular phosphatase domain s. An alternatively spliced mini-exon was identified in the extracellu lar segment of RPTP rho, between the fourth fibronectin type II repeat and the transmembrane domain. The RPTR rho gene was mapped to human c hromosome 20 and mouse chromosome 2, Northern blot analysis demonstrat ed that RPTP rho expression was restricted to the central nervous syst em, and in situ hybridization studies showed that the RPTP rho transcr ipt was distributed throughout the murine brain and spinal cord. Excep tionally high levels of the transcript were present in the cortex and olfactory bulbs during perinatal development, but were down-regulated during postnatal week two. The motifs found in the extracellular segme nt of type II receptor protein tyrosine phosphatases are commonly foun d in neural cell adhesion molecules, suggesting that RPTP rho may be i nvolved in both signal transduction and cellular adhesion in the centr al nervous system. (C) 1998 Elsevier Science B.V.