The invention provides a cosmetic or pharmaceutical composition comprising, in a physiologically acceptable medium, at least one purified natural or synthetic polypeptide wherein the peptide sequence is represented wholly or partly by at least one sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 16, SEQ ID NO: 25 and SEQ ID NO: 27 and their homologs.