A short peptide is a protein kinase C (PKC) α‐specific substrate

Abstract

The purpose of this study was to find protein kinase C (PKC) isozyme-specific peptides. A peptide library containing 1772 sequences was designed using Scansite and screened by MALDI-TOF MS and kinase activity assays for PKC isozyme-specificity. A peptide (Alphatomega; H-FKKQGSFAKKK-NH(2)) with high specificity for PKC alpha relative to other isozymes was identified. The peptide was phosphorylated to a greater extent by tissue lysates from B16 melanoma, HepG2, and human breast cancer, which had higher levels of activated PKC alpha, when compared to normal skin, liver, and human breast tissue lysates, respectively. Moreover, addition of Ro-31-7549, an inhibitor with great specificity for PKC alpha, to the phosphorylation reaction caused a dose-dependent reduction in phosphorylation, but no inhibition was identified with the addition of rottlerin and H-89. These results show that this peptide has great potential as a PKC alpha-specific substrate.

Effect of peptide content on the regulation of transgene expression by protein kinase Cα-responsive linear polyethylenimine-peptide conjugates

“…PKs play important roles in regulating various cellular functions; therefore dysregulation of PK activities is closely associated with many diseases, including cancers [26][27][28][29]. Amongst the various PKs, protein kinase C␣ (PKC␣) is a suitable marker that distinguishes cancer cells from healthy cells because PKC␣ activity is much higher in various types of cancer cells than in healthy cells [30][31][32][33][34]. Recently, we described a PKC␣-responsive linear PEI (LPEI)-peptide conjugate comprised of LPEI in the main chain and cationic a PKC␣ peptide substrate (FKKQGSFAKKK-NH 2 ) in the side chain [18].…”

Peptide substrates for G protein‐coupled receptor kinase 2

“…Using a motif-based profile scanning approach, combined with synthetic peptide chemistry, our group has developed highly specific peptide substrates for protein kinase Ca [34], Ij-B kinase b [35], and Rhoassociated protein kinase 2 (Rho kinase 2/ROCK2) [36]. However, consensus motifs for the substrates of GRK2 have not yet been described [37].…”

Role of estrogenic compounds (diethylstibestrol, 17β‐estradiol, and bisphenol A) in the phosphorylation of substrate by protein kinase Cα

“…Recently, we found a PKCα-specific substrate (FKKQGSFAKKK), which proved useful as a substrate for the phosphorylation reaction of PKCα [16]. Moreover, many different matrixes for the MALDI-TOF MS analysis have been developed, but CHCA and 2,5-dihydrozybenzoic acid are considered to be good matrixes for the analysis of peptides and proteins [17].…”