Antennapedia/HS1 chimeric phosphotyrosyl peptide: conformational properties, binding capability to c-Fgr SH2 domain and cell permeability.
With the aim of interfering with the signaling pathways mediated by the SH2 domains of Src-like tyrosine kinases, we synthesized a tyrosyl-phospho decapeptide, corresponding to the sequence 392-401 of HS1 protein, which inhibits the secondary phosphorylation of HS1 protein catalyzed by the Src-like kinases c-Fgr or Lyn. This phospho-peptide was modified to enter cells by coupling to the third helix of Antennapedia homeodomain, which is able to translocate across cell membranes. Here we present CD and fluorescence studies on the conformational behavior in membrane-mimicking environments and on lipid interactions of Antennapedia fragment and its chimeric phosphorylated and unphosphorylated derivatives. These studies evidenced that electrostatic rather than amphiphilic interactions determine the peptide adsorption on lipids. Experiments performed with recombinant protein containing the SH2 domain of c-Fgr fused with GST and with isolated erythrocyte membranes demonstrated that the presence of the N-terminal Antennapedia fragment only slightly affects the binding of the phospho-HS1 peptide to the SH2 domain. In fact, it has been shown that in isolated erythrocyte membranes, both phospho-HS1 peptide and its chimeric derivative greatly affect either the SH2-mediated recruitment of the c-Fgr to the transmembrane protein band 3 and the following phosphorylation of the protein catalyzed by the Src-like kinase c-Fgr. The ability of the chimeric phospho-peptide to enter cells has been demonstrated by confocal microscopy analysis.
Ruzza
P
P
CNR-Biopolymers Research Center, via Marzolo 1, Padua, 35131 Italy. paolo.ruzza@unipd.it
Donella-Deana
A
A
Calderan
A
A
Brunati
A
A
Massimino
M L
ML
Elardo
S
S
Mattiazzo
A
A
Pinna
L A
LA
Borin
G
G
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D051943:Antennapedia Homeodomain Protein; D001667:Binding, Competitive; D001798:Blood Proteins / Q000737:chemistry*; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism; D002942:Circular Dichroism; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000378:metabolism; D018398:Homeodomain Proteins / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D050356:Lipid Metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014157:Transcription Factors; D014364:Tryptophan / Q000378:metabolism; D018909:src Homology Domains; D019061:src-Family Kinases
D048868:Adaptor Proteins, Signal Transducing; D051943:Antennapedia Homeodomain Protein; D001798:Blood Proteins; C061909:HCLS1 protein, human; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010455:Peptides; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D014364:Tryptophan; C053102:proto-oncogene proteins c-fgr; D019061:src-Family Kinases