Optimization of the cellular import of functionally active SH2-domain-interacting phosphopeptides

• Published in: Cellular and molecular life sciences : CMLS Vol. 63; no. 22; pp. 2682 - 2693
• Main Authors: Kertész, A, Váradi, G, Tóth, G K, Fajka-Boja, R, Monostori, E, Sármay, G
• Format: Journal Article
• Language: English
• Published: Switzerland Springer Nature B.V 01-11-2006; Birkhäuser-Verlag
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Amino Acid Motifs; B-Lymphocytes - metabolism; Burkitt Lymphoma - metabolism; Cellular biology; Enzymes; Humans; Peptides; Permeability; Phosphopeptides - chemistry; Phosphopeptides - metabolism; Phosphopeptides - pharmacology; Phosphoproteins - metabolism; Phosphorylation; Phosphotyrosine - metabolism; Signal Transduction; src Homology Domains
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-006-6346-6

Phosphopeptides interacting with src homology 2 (SH2) domains can activate essential signaling enzymes in vitro. When delivered to cells, they may disrupt protein-protein interactions, thereby influencing intracellular signaling. We showed earlier that phosphopeptides corresponding to the inhibitory motif of Fcgamma receptor IIb and a motif of the Grb2-associated binder 1 adaptor protein activate SH2-containing tyrosine phosphatase 2 in vitro. To study the ex vivo effects of these peptides, we have now compared different methods for peptide delivery: (i) permeabilization of the target cells and (ii) the use of cell-permeable vectors, which are potentially able to transport biologically active compounds into B cells. We found octanoyl-Arg(8) to be an optimal carrier for the delivery of phosphopeptides to the cells. With this strategy, the function of cell-permeable SHP-2-binding phosphopeptides was analyzed. These peptides modulated the protein phosphorylation in B cells in a dose- and time-dependent manner.