※ RPTP family introduction

    RPTP belong to the Classical Protein Tyrosine Phosphatase (classical PTP). RPTP, also known as receptor protein tyrosine phosphatase, is defined by its extracellular domains, which function as upstream signal receptor. Some phosphatase contain large extracellular domain while others contain small extracellular domain. RPTP members function its phosphatase activity utilizing its cytoplasmic domains. Most members contain two phosphatase domain, named D1(membrane proximal) and D2. D1 domain is responsible for 99% of catalytic activity, while the second phosphatase domain D2 appears to bind multiple downstream partners. Although D2 is inactive, it can be converted to a catalytic active domain by change two amino acids (KNRLVN and WPEQGVP) (1). RPTP family is involved in varieties of cellular processes. DLAR, DPTP10D and DPTP99A phosphatase are highly expressed in the growth cones of motor neuron axons, suggesting the RPTP play an important role in axon guidance. CDC45 is expressed exclusively in the haematopoietic system and involved in TCR cell signaling. RPTPalpha is highly expressed in the developing brain of various species, especially expressed in glia, suggesting that RPTPalpha is involved in controlling neuronal migration (2).

Reference
1. Johnson, K.G. and Van Vactor, D. (2003) Receptor protein tyrosine phosphatases in nervous system development. Physiol Rev, 83, 1-24. PMID: 12506125.
2. den Hertog, J., Blanchetot, C., Buist, A., Overvoorde, J., van der Sar, A. and Tertoolen, L.G. (1999) Receptor protein-tyrosine phosphatase signalling in development. Int J Dev Biol, 43, 723-733. PMID: 10668981