Details

Autor(en) / Beteiligte

• Campana, W.Marie
• Hiraiwa, Masao
• Addison, Kevin C.
• O'brien, John S.

Titel

Induction of MAPK Phosphorylation by Prosaposin and Prosaptide in PC12 Cells

Ist Teil von

• Biochemical and biophysical research communications, 1996-12, Vol.229 (3), p.706-712

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1996

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• Prosaposin is a 66 kDa glycoprotein which has neurotrophic activityin vitroandin vivo.The neurotrophic sequence (8CEFLVKEVTKLIDNNKTEKEI29L) within prosaposin has been located to the amino terminal portion of the saposin C domain. This 22-mer peptide, prosaptide, has neurotrophic activity equivalent to prosaposin. We present binding studies using125I-prosaposin and125I-prosaptide which revealed a single class of specific binding sites with a Kd of 2.5 nM and 18.3 nM, respectively. Both prosaposin and prosaptide rapidly stimulated protein tyrosine phosphorylation in PC12 cells and increased phosphorylation of MAPK 20-fold especially of p44 MAPK which peaked at 5 minutes of stimulation and then rapidly declined. Treatment of PC12 cells with a mutant 22-mer prosaptide (21Asn to21Asp) did not induce phosphorylation. These findings suggest a role for MAPK in signal transduction by prosaposin.