Downregulation of LAR tyrosine phosphatase prevents apoptosis and augmentsNGF-induced neurite outgrowth

The identity of the protein tyrosine phosphatases (PTPs) regulating cell de ath and responses to neurotrophins during neural development remain unknown . To determine if the leukocyte common antigen-related (LAR) PTP regulates these processes, PC12 cells were made LAR-deficient via stable transfection with an LAR antisense transgene. LAR-deficient cells demonstrated a stable novel phenotype, including a two-fold increase in nerve growth factor- but not fibroblast growth factor-induced neurite outgrowth. Upon serum-depriva tion, LAR-deficient cells exhibited a two- to three-fold decrease in cell d eath, The findings that an endogenous PTP promotes cell death and counter-r egulates neurotrophin actions introduce a major new receptor gene family to neurotrophic processes and suggest novel strategies for preventing cell de ath and augmenting neurotrophin function. (C) 2000 John Wiley & Sons, Inc.*