RAB4A Knockout HAP1 Cell Line

The choice depends on whether you are studying RAB4A's role in fast endocytic recycling from early endosomes or its contributions to receptor trafficking and immune cell biology. The Knockout line is the standard tool for asking whether RAB4A is required for these processes — RAB4A regulates the fast recycling pathway returning cargo from early endosomes directly to the plasma membrane, distinct from the slower RAB11-dependent perinuclear recycling. Overexpression is useful for studying RAB4A trafficking dynamics or for testing GTPase cycle mutants. For endocytic trafficking research, the EDITGENE RAB4A Knockout in HAP1 enables mechanistic dissection of fast versus slow recycling pathways. RAB4B paralog expression should be assessed. Rescue with wild-type, constitutively active (Q72L), or dominant negative (S22N) RAB4A enables comprehensive GTPase cycle studies. RAB4A is implicated in T cell receptor recycling and immune synapse dynamics.

Primary applications: • Fast endocytic recycling: fluorescent transferrin or surface receptor recycling kinetics to characterize RAB4A-dependent fast recycling. • Receptor trafficking studies: GPCR (e.g., β2-AR), transferrin receptor, and integrin recycling analysis given RAB4A's role in fast recycling. • Immune cell biology: TCR recycling and immune synapse dynamics where RAB4A has been characterized in T cell biology. • Endocytic pathway dissection: comparison with RAB5 (early endosome) and RAB11 (slow recycling) for pathway-specific function characterization. EDITGENE recommends this model for researchers investigating endocytic recycling, receptor trafficking, and RAB GTPase pathway biology.

Yes. RAB4A rescue experiments require attention to GTPase cycle and recycling pathway specificity: • Construct design: use a codon-modified RAB4A sequence with a small N-terminal tag (FLAG, HA, GFP). RAB4A has C-terminal CAAX motif for prenylation — preserve C-terminus. • GTPase cycle rescue: Q72L (constitutively active) and S22N (dominant negative) mutants enable cycle-specific studies. • Pathway specificity: rescue with wild-type RAB4A restores fast recycling specifically (distinct from RAB11-dependent slow recycling). • Functional readout: rescue should restore fast recycling kinetics measured by fluorescent transferrin recycling. HAP1-specific considerations: • Diploidization: HAP1 cells gradually diploidize during extended culture — confirm ploidy by flow cytometry at the time of phenotypic assay. • Integration site sensitivity: position effects on transgene expression are more pronounced in near-haploid backgrounds; generating multiple independent rescue clones is strongly recommended. • Transduction efficiency: HAP1 transduces with lentivirus at moderate efficiency — increase MOI compared to standard immortalized lines.