Regulation of an S6/H4 Kinase in Crude Lymphosarcoma P1798 Preparations

• Main Author: Taylor, Allison Antoinette
• Other Authors: Masaracchia, Ruthann A.
• Format: Others
• Language: English
• Published: University of North Texas 1998
• Subjects: protein kinases; phosphorylation; lymphomas; Protein kinases.; Phosphorylation.; Lymphomas.
• Online Access: https://digital.library.unt.edu/ark:/67531/metadc501281/

Purified S6/H4 kinase (Mr 60,000) requires autophosphorylation for activation. A rabbit anti-S6/H4 kinase peptide (SVIDPVPAPVGDSHVDGAAK) antibody recognized both the S6/H4 kinase holoenzyme and catalytic domain. Immunoreactivity with p60 kinase protein, and S6/H4 kinase activity were precisely correlated in fractions obtained from ion exchange chromatography of P1798 lymphosarcoma extracts. An enzyme which catalyzed the MgATP-dependent phosphorylation and activation of S6/H4 kinase coeluted with immunoreactivity from Mono 5, but not Mono Q chromatography. Since S6/H4 kinase is homologous with rac-activated PAK65, the observation that phosphorylation is also required for activation suggests a complex mechanism for in vivo activation of the S6/H4 kinase.