The M protein has a crucial role in virus assembly and interacts with the RNP complex as well as with the viral membrane. MTEIYDFDKSAWDIKGSIAPTQPTTHSEGRLVPQVRVIDPGPGDRKDECLMYMSLLGVVEDSDPLGPPIGRAFGSPPLGVGRSTAKPEELLKEATELDIVVRRTAGLNEKLVFYNNTPLTLPTPWRKVPTTGSVFNANQVCNAVNLTPLDTPQRFRVVYTSITRLSDNGHYTVPRRMLEFRSVNAVAFNLLATLRIDKAIGHGKIIDNAEQLPEATFMVHIGNFRRKKSEVYSADHCKMEIEKMGLVFALGGIGGTSPHIRSTGKMSKTLHAQLGFKKTLCYPLMDINEDLNRLLWRSRCKIARIQAVLQPSVPQEFRIYDDVIINDDQGLFKALQTVVPSNA M MATRX_MEASB Matrix protein 343