The present invention relates to compositions and methods relating to the
characterization and function of RPTPB. Specifically, the present
invention provides transgenic animals comprising disruptions in a RPTPB
gene and methods of treating diseases conditions, such as depression. The
present invention further relates to agents that modulate RPTPB and
methods of screening for agents that modulate RPTPB for the treatment of
diseases and conditions such as depression.