CD148, a new membrane tyrosine phosphatase involved in leukocyte function

Protein tyrosine phosphatases play an essential role in the control of leuc ocyte cell growth an differentiation. Recently a new receptor type membrane tyrosine phosphatase named CD148 has been identified. This molecule is pre sent on the membrane of all the hematopoietic lineages as well as on severa l other cell types, mainly epithelial cells and its expression increases af ter cell activation. This molecule is able to act as a transducing molecule . Moreover, CD148 is able to modulate the signal transduction through the T CR/CD3 complex, in a manner similar to CD45, It has also been suggested tha t CD148 could be involved in mechanisms of differentiation and inhibition o f cell growth. In addition, CD148 seems to be associated with a serine/thre onine kinase in certain epitelial cell lines and leucocytes. Here, we revie w recent data on the expression and function of CD148 in both human, mouse and rat.