Polypeptide, of at most 350 amino acids, comprising, from N-terminal to C-terminal, optionally, a signal peptide, a domain for anchoring said polypeptide into the reticulum membrane and/or Golgi membrane ( i.e., the anchoring domain), and a domain exposed cytoplasmically ( i.e., the cytoplasmic domain) when the polypeptide is anchored in the membrane, wherein said cytoplasmic domain ends with a MAST-2 binding domain, wherein the size of said MAST-2 binding domain is from 11 to 13 amino acid residues, the first two residues of said MAST-2 binding domain are S and W, and the last four residues of said MAST-2 binding domain are Q, T, R and L, said MAST-2 binding domain being selected from the group consisting of: a sequence, whose size is 11 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 QTRL, wherein each of X 1, X 2, X 3, X 4 and X 5 is any amino acid residue (SEQ ID NO:19), wherein X 1 is any amino acid, preferably E or A (SEQ ID NOs: 20 and 21), more preferably E, and/or X 2 is S, E or V, more preferably V (SEQ ID NOs: 22 to 24); a sequence, whose size is 11 residues, selected from the group consisting of: SWX 1 KSGGQTRL (SEQ ID NO:76), SWX 1 SSGGQTRL (SEQ ID NO:77), SWX 1 SHGGQTRL (SEQ ID NO:78), SWX 1 SHKGQTRL (SEQ ID NO:79), SWX 1 SHKSQTRL (SEQ ID NO:80), SWX 1 HSGGQTRL (SEQ ID NO:86), SWX 1 HKGGQTRL (SEQ ID NO:87), SWX 1 HKSGQTRL (SEQ ID NO:88), SWX 1 SKGGQTRL (SEQ ID NO:89), SWX 1 SKSGQTRL (SEQ ID NO:90), SWX 1 SHSGQTRL (SEQ ID NO:91), SWX 1 SHKGQTRL (SEQ ID NO:92) and SWX 1 SKGGQTRL (SEQ ID NO:93), wherein X 1 is any amino acid, preferably E or A, more preferably E (SEQ ID NOs: 81 to 85 and 94 to 101); a sequence, whose size is 12 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 X 6 QTRL, wherein each of X 1, X 2, X 3, X 4, X 5 and X 6 is any amino acid residue (SEQ ID NO:112), wherein X 1 is preferably E or A, more preferably E and/or X 2 is S, E or V, more preferably V; and a sequence, whose size is 12 residues, selected from the group consisting of: SWX 1 HKSGGQTRL (SEQ ID NO:102), SWX 1 SKSGGQTRL (SEQ ID NO:103), SWX 1 SHSGGQTRL (SEQ ID NO:104), SWX 1 SHKGGQTRL (SEQ ID NO:105) and SWX 1 SHKSGQTRL (SEQ ID NO:106), wherein X 1 is any amino acid, preferably E or A, more preferably E (SEQ ID NOs 107 to 111); a sequence, whose size is 13 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 X 6 X 7 QTRL, wherein each of X 1, X 2, X 3, X 4, X 5, X 6 and X 7, is any amino acid residue (SEQ ID NO:192), wherein said sequence does not consist of SWESHKSGGQTRL (SEQ ID NO:1), wherein said polypeptide presents a binding affinity for the PDZ domain of the human MAST2 protein which is higher than the binding affinity of rabies virus G protein comprising the SWESHKSGGQTRL sequence for the PDZ domain of the MAST2 protein. a sequence, whose size is 11 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 QTRL, wherein each of X 1, X 2, X 3, X 4 and X 5 is any amino acid residue (SEQ ID NO:19), wherein X 1 is any amino acid, preferably E or A (SEQ ID NOs: 20 and 21), more preferably E, and/or X 2 is S, E or V, more preferably V (SEQ ID NOs: 22 to 24); a sequence, whose size is 11 residues, selected from the group consisting of: SWX 1 KSGGQTRL (SEQ ID NO:76), SWX 1 SSGGQTRL (SEQ ID NO:77), SWX 1 SHGGQTRL (SEQ ID NO:78), SWX 1 SHKGQTRL (SEQ ID NO:79), SWX 1 SHKSQTRL (SEQ ID NO:80), SWX 1 HSGGQTRL (SEQ ID NO:86), SWX 1 HKGGQTRL (SEQ ID NO:87), SWX 1 HKSGQTRL (SEQ ID NO:88), SWX 1 SKGGQTRL (SEQ ID NO:89), SWX 1 SKSGQTRL (SEQ ID NO:90), SWX 1 SHSGQTRL (SEQ ID NO:91), SWX 1 SHKGQTRL (SEQ ID NO:92) and SWX 1 SKGGQTRL (SEQ ID NO:93), wherein X 1 is any amino acid, preferably E or A, more preferably E (SEQ ID NOs: 81 to 85 and 94 to 101); a sequence, whose size is 12 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 X 6 QTRL, wherein each of X 1, X 2, X 3, X 4, X 5 and X 6 is any amino acid residue (SEQ ID NO:112), wherein X 1 is preferably E or A, more preferably E and/or X 2 is S, E or V, more preferably V; and a sequence, whose size is 12 residues, selected from the group consisting of: SWX 1 HKSGGQTRL (SEQ ID NO:102), SWX 1 SKSGGQTRL (SEQ ID NO:103), SWX 1 SHSGGQTRL (SEQ ID NO:104), SWX 1 SHKGGQTRL (SEQ ID NO:105) and SWX 1 SHKSGQTRL (SEQ ID NO:106), wherein X 1 is any amino acid, preferably E or A, more preferably E (SEQ ID NOs 107 to 111); a sequence, whose size is 13 residues, consisting of SWX 1 X 2 X 3 X 4 X 5 X 6 X 7 QTRL, wherein each of X 1, X 2, X 3, X 4, X 5, X 6 and X 7, is any amino acid residue (SEQ ID NO:192), wherein said sequence does not consist of SWESHKSGGQTRL (SEQ ID NO:1),