Membrane-associated RING-CH-type finger protein 9 (MARCH9)

Membrane-associated RING-CH-type finger protein 9 (MARCH9) is an E3 ubiquitin ligase that plays a crucial role in the regulation of immune responses through its action on membrane proteins. It catalyzes the transfer of ubiquitin from E2 ubiquitin-conjugating enzymes to substrate proteins, particularly immune-related surface molecules such as major histocompatibility complex class I (MHC I), targeting them for endocytosis and lysosomal degradation. This downregulation of MHC I on antigen-presenting cells affects the ability of the immune system to recognize and respond to infected or malignant cells. The MARCH family of proteins, including MARCH9, are structurally homologous to viral immunosuppressive ligases and are emerging as important regulators and potential therapeutic targets in immunity, infection, and cancer[1][2][3].

Other names

MARCH9E3 ubiquitin-protein ligase MARCH9

Ubiquitination of surface proteins (such as MHC I), leading to their internalization and degradation in the lysosome