Physiological signaling specificity by protein tyrosine phosphatases.

Protein tyrosine phosphatases (PTPs) are now recognized to be involved in a multitude of signaling events that control fundamental biological processes such as cell growth, differentiation, apoptosis, and cell movement. PTPs, which were initially thought to be less discriminating in their actions compared with their protein tyrosine kinase counterparts, are now known to regulate these various biological processes in a precise manner. This review will focus on the concept that PTPs exhibit remarkable signaling specificity through intrinsic differences between their PTP domains and through various modes of regulation that endows them with the capacity to promote unique physiological responses.