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. Inhibits mRNA nuclear export through direct interaction with host RAE1-NUP98 complex, thereby preventing interferon signaling and establishment of antiviral state in infected cells. Induces cell-rounding, cytoskeleton disorganization and apoptosis in infected cell. Inhibits host transcription, possibly through interaction with host DNA repair factor IIH/TFIIH GTF2H5 subunit (By similarity). Homomultimer. Interacts with viral nucleocapsid. Interacts with host NEDD4 and TSG101. Interacts with host dynamin. Interacts with host RAE1-NUP98 complex. Interacts with host NDUFAF4; the interaction inhibits viral propagation and is independent of interferon activation. Interacts with host GTF2H5; the interaction may inhibit host transcription. 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 two overlapping L domains: a PPXY motif which interacts with the WW domain 3 of NEDD4 and a PTAP/PSAP motif, which interacts with the UEV domain of TSG101. Phosphorylated by host. VSV is used as an oncolytic agent for cancer therapy, because of his wide host range, rapid replication and mild pathogenicity in humans. VSV used are mutated at M51R in their matrix protein. These mutated viruses cannot successfully infect normal cells, being unable to counteract the antiviral state induced by interferon-alpha in normal cells. Cancer cells are impeded with responsiveness to interferon, and then can be successfully infected and lysed by the virus. Most abundant protein in the virion. Belongs to the vesiculoviruses matrix protein family.