Abstract
The receptor interacting serine/threonine kinase1 and 3 (RIPK1, RIPK3) are regulators
of cell death and survival. RIPK1 kinase activity is required for necroptosis and
apoptosis, while its scaffolding function is necessary for survival. Although both
proteins can mediate apoptosis, RIPK1 and RIPK3 are most well-known for their role
in the execution of necroptosis via the mixed lineage domain like pseudokinase. Necroptosis
is a caspase-independent regulated cell death program which was first described in
cultured cells with unknown physiologic relevance in the liver. Many recent reports
have suggested that RIPK1 and/or RIPK3 participate in liver disease pathogenesis and
cell death. Notably, both proteins have been shown to mediate inflammation independent
of cell death. Whether necroptosis occurs in hepatocytes, and how it is executed in
the presence of an intact caspase machinery is controversial. In spite of this controversy,
it is evident that RIPK1 and RIPK3 participate in many experimental liver disease
models. Therefore, in addition to cell death signaling, their necroptosis-independent
role warrants further examination.
Keywords
RIPK1 - RIPK3 - cell death - necroptosis - apoptosis