| Negative regulation of HER 2 signaling by the PEST type protein tyrosine phosphatase BDP 1 . ^^^ We investigated the role of the PEST type protein tyrosine phosphatase BDP 1 in the regulation of HER 2 , a member of the epidermal growth factor receptor ( EGFR ) family of RTKs . ^^^ Here we demonstrate that HER 2 signaling is highly sensitive to BDP 1 activity . ^^^ Overexpression of BDP 1 inhibited ligand induced activation of HER 2 but not that of the closely related EGFR . ^^^ On the other hand , suppression of endogenous BDP 1 expression increased the phosphorylation state of HER 2 . ^^^ |