The rabies virus matrix protein (RABV M) interacts with host histone deacetylase 6 (HDAC6) to activate the MEK/ ERK signaling pathway and enhance viral replication.

Rabies virus (RABV) is the causative agent of rabies, posing a severe threat to human and animal health. The matrix (M) protein of RABV plays crucial roles during viral infection. In this study, we identified RABV M protein interacted with host histone deacetylase 6 (HDAC6) through a combination of immunoprecipitation and mass spectrometry analysis. Specifically, the catalytic domains of HDAC6 (amino acids 435-835) was shown to be critical for the interaction between HDAC6 and the RABV M protein. Overexpression of HDAC6 significantly enhanced RABV replication, whereas inhibition of HDAC6 expression or its deacetylase activity had the opposite effect，indicating that HDAC6 is a positive regulator of RABV replication. We further determined that RABV infection actives the MEK/ERK pathway, and inhibition of this pathway with U0126 significantly reduced viral titers. Moreover, HDAC6 positively regulated MEK/ERK pathway activation in a manner independent of its deacetylase activity but dependent on the presence of HDAC6 during virus infection. Finally, we demonstrated that co-expression of RABV M enhanced the role of HDAC6 in facilitating MEK/ERK pathway activation. Collectively, our findings demonstrate that RABV exploits the HDAC6-M interaction to hijack the MEK/ERK signaling axis, which is essential for viral replication. Notably, HDAC6 facilitates MEK/ERK activation in a deacetylase activity-independent manner, revealing a novel mechanism by which viruses manipulate host machinery. These results highlight HDAC6 as a potential therapeutic target for combating rabies.