Plays a major role in assembly and budding of virion, by recruiting cellular partners of the ESCRT complexes that play a key role in releasing the budding particle from the host membrane. Condensates the ribonucleocapsid core during virus assembly. Homomultimer. Interacts with viral nucleocapsid. Interacts with host NEDD4. Late-budding domains (L domains) are short sequence motifs essential for viral particle budding. They recruit proteins of the host ESCRT machinery (Endosomal Sorting Complex Required for Transport) or ESCRT-associated proteins. M contains a PPXY motif which interacts with the WW domain 3 of NEDD4. Phosphorylated by host. Most abundant protein in the virion. Belongs to the vesiculoviruses matrix protein family.