![Fig. 5. Treatment with forskolin or PGE1 increases phosphorylation of GPIbβ in GPIb/V/IX-transfected cells and platelets, an effect reversed by RAM.1. / K562-GPIb/V/IX, K562-GPIb(βSer166Gly)/V/IX cells, or human platelets were labeled with [32P]PO4, then preincubated with 10 μg/mL RAM.1 (+) or rat control IgG (-) and treated with dimethyl sulfoxide (resting), 10 μM PGE1 (+PGE1), or 10 μM forskolin (+Fsk) for 10 minutes at 37°C. Following cell lysis, the GPIb/V/IX complex was immunoprecipitated by RAM.1 and proteins were separated on a 7.5%-15% SDS-PAGE gel. Gels were analyzed by autoradiography or using the phosphoimager system. Results are representative of 2 separate experiments. Forskolin or PGE1 treatment increased the GPIbβ phosphorylation on both platelets and K562-GPIb/V/IX cells whereas RAM.1 switched it off. In contrast, forskolin and PGE1 had no effect on phosphorylation of the GPIbβ(Ser166Gly) subunit.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/101/9/10.1182_blood-2002-06-1847/4/h80934215005.jpeg?Expires=1735514955&Signature=dePKHPgx4W3Y4EPDehn1M6KLI0e5G7UHlcVdr3nqQ0JHAtUps6opsYOMmzKX7oCfFREZrWWDnhGsAX8kKB8JdDGi2utZ-hxGmTG3PvfiGtw55Q3P7foOmF7GRHM7bCnj~AWPw2FVBFsV8uncxeIuciAgz7JEewIKNb-VKnXGkHhxaIXBIFBJvIhxrJcU6rs7LzV70uvKoEuTTCr9QYb~YQsaeR783KvlLoPNKsTHt7o0Pd7EJItkZVQHESrOdOaiuvm32zlxvdieFx56psiJIRiyUCAP8hMhGVgg2r3pn2-y3YqiH1v1eg3ppYk7MeQHOM4H266AeVZTevIbz0ARuA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Treatment with forskolin or PGE1 increases phosphorylation of GPIbβ in GPIb/V/IX-transfected cells and platelets, an effect reversed by RAM.1.
K562-GPIb/V/IX, K562-GPIb(βSer166Gly)/V/IX cells, or human platelets were labeled with [32P]PO4, then preincubated with 10 μg/mL RAM.1 (+) or rat control IgG (-) and treated with dimethyl sulfoxide (resting), 10 μM PGE1 (+PGE1), or 10 μM forskolin (+Fsk) for 10 minutes at 37°C. Following cell lysis, the GPIb/V/IX complex was immunoprecipitated by RAM.1 and proteins were separated on a 7.5%-15% SDS-PAGE gel. Gels were analyzed by autoradiography or using the phosphoimager system. Results are representative of 2 separate experiments. Forskolin or PGE1 treatment increased the GPIbβ phosphorylation on both platelets and K562-GPIb/V/IX cells whereas RAM.1 switched it off. In contrast, forskolin and PGE1 had no effect on phosphorylation of the GPIbβ(Ser166Gly) subunit.
