A sphingosine-dependent protein kinase that specifically phosphorylates 14-3-3 (SDK1) is identified as the kinase domain of PKCdelta: a preliminary note.
A specific protein kinase that phosphorylates Ser60, Ser59, or Ser58 of 14-3-3beta, eta, or zeta, respectively, only in the presence of sphingosine (Sph) or N,N-dimethyl-Sph (DMS), was termed "sphingosine-dependent protein kinase-1" (SDK1) [J. Biol. Chem. 273(34) (1998) 21834]. We have now identified SDK1 as a protein having the same amino acid sequence as in the C-terminal-half kinase domain of PKCdelta, with approximately 40 kDa molecular mass, based on large-scale purification of a protein from rat liver, and partial sequence using three different combinations of LC-MS or LC-MS/MS with respective search engine. PKCdelta did not display any SDK1 activity and PKCdelta activity was inhibited by Sph and DMS. However, strong SDK1 activity, only in the presence of Sph or DMS, became detectable when PKCdelta was incubated with caspase-3, which releases the approximately 40 kDa kinase domain.
Hamaguchi
Akikazu
A
Department of Pathobiology, University of Washington, Seattle, WA, USA.
Suzuki
Erika
E
Murayama
Kimie
K
Fujimura
Tsutomu
T
Hikita
Toshiyuki
T
Iwabuchi
Kazuhisa
K
Handa
Kazuko
K
Withers
Donald A
DA
Masters
Shane C
SC
Fu
Haian
H
Hakomori
Senitiroh
S
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D020134:Catalytic Domain; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008969:Molecular Sequence Data; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000737:chemistry* / Q000378:metabolism; D051745:Protein Kinase C-delta; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013110:Sphingosine / Q000378:metabolism; D013379:Substrate Specificity; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D048948:14-3-3 Proteins; D004791:Enzyme Inhibitors; D010455:Peptides; D014446:Tyrosine 3-Monooxygenase; C497260:Prkcd protein, rat; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D013110:Sphingosine