The GULP1 Knockout SK-HEP-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human SK-HEP-1 cell line, engineered for disruption of the GULP1 gene. GULP1 encodes an engulfment adaptor protein critical for the recognition and clearance of apoptotic cells and cellular debris. This polyclonal knockout pool provides a genetically heterogeneous loss-of-function model, enabling robust investigation of GULP1-dependent signaling in a liver endothelial-like context without the limitations associated with clonal selection.
The SK-HEP-1 host cell line was originally established from the ascites of a patient with liver adenocarcinoma and exhibits endothelial-like characteristics, making it a valuable model for studying liver sinusoidal endothelial cell biology. These cells form the lining of hepatic sinusoids and participate in blood filtration, nutrient exchange, and immune surveillance. Their partial endothelial phenotype provides a unique platform to examine phagocytic and endocytic processes relevant to the liver microenvironment.
GULP1 functions as a central adaptor downstream of phosphatidylserine receptors such as MEGF10, linking apoptotic cell recognition to cytoskeletal remodeling events required for engulfment. Upon receptor activation by phosphatidylserine-exposing apoptotic targets or complement C1q, GULP1 interacts with the DOCK180?CELMO complex, which acts as a guanine nucleotide exchange factor (GEF) for the small GTPase RAC1. Activated RAC1 promotes actin nucleation via the Arp2/3 complex, driving pseudopod extension and phagosome formation. Additional interacting partners include CrkII and clathrin, which participate in receptor trafficking and phagosome maturation, ultimately leading to lysosomal degradation of engulfed cargo.
In the context of SK-HEP-1 cells, the GULP1 knockout disrupts the normal efferocytosis pathway, offering a powerful tool to examine how impaired apoptotic cell clearance influences liver tissue homeostasis and disease. Given the role of GULP1 in engulfment signaling, this model is highly relevant for dissecting mechanisms of immune evasion in hepatocellular carcinoma, where tumor cells may manipulate phagocytic clearance to survive and resist therapy. The polyclonal knockout population, when compared to wild-type SK-HEP-1, allows for the assessment of GULP1??s contribution to actin-dependent processes such as cell migration and invasion, as well as its impact on drug sensitivity, particularly to agents like sorafenib.
Researchers can employ these cells in a wide array of functional assays, including phagocytosis assays with labeled apoptotic targets to quantify engulfment efficiency, co-immunoprecipitation to map GULP1 interactomes, and flow cytometry to monitor phospho-signaling events such as RAC1 activation. Additionally, RT-qPCR and Western blotting confirm GULP1 disruption, while migration and invasion assays explore cytoskeletal-dependent phenotypes. Drug sensitivity profiling in the presence or absence of GULP1 expression can reveal new therapeutic vulnerabilities. For further technical details, please contact Ascent Research.
