The DLG4 Knockout HAP1 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal population of HAP1 cells harboring targeted disruption of the human DLG4 gene. This gene encodes postsynaptic density protein 95 (PSD-95), a master scaffold at excitatory synapses. The polyclonal knockout pool provides a genetically defined loss-of-function model for studying PSD-95 biology, eliminating concerns of clonal variability and enabling robust experimental designs that average out single-cell artifacts. Each lot is validated for gene disruption at the population level, ensuring consistent depletion of PSD-95 protein expression.
The parental HAP1 cell line is a near-haploid, adherent fibroblast-like line derived from the KBM-7 chronic myeloid leukemia isolate. It retains a single copy of most chromosomes, except for chromosome 8 and a portion of chromosome 15, yielding a simplified genomic landscape ideal for genetic manipulation. This near-haploidy facilitates efficient CRISPR/Cas9-mediated knockout without the confound of a second allele, and the cells maintain stable growth and a consistent phenotype. HAP1 is widely used in functional genomic screens and mechanistic studies, making it a versatile host for knockout models.
PSD-95 functions as a central organizer of excitatory postsynaptic specializations. Through its PDZ, SH3, and guanylate kinase-like domains, it simultaneously clusters NMDA-type glutamate receptors (GluN2A/GluN2B), AMPA-type receptors (GluA1/GluA2), and the potassium channel Kv1.4, while recruiting key signaling enzymes. It interacts directly with neuronal nitric oxide synthase (nNOS), the GTPase-activating protein SynGAP, guanylate kinase-associated protein (GKAP), and Shank scaffold proteins. PSD-95 is activated by calcium influx via NMDA receptors and is phosphorylated by CaMKII, Fyn tyrosine kinase, and protein kinase A (PKA); palmitoylation by DHHC2/3/15 acyltransferases regulates its membrane targeting. This assembly facilitates localized signaling from NMDA receptors to downstream effectors such as nNOS and SynGAP, thereby governing dendritic spine morphogenesis and synaptic plasticity.
Although HAP1 cells are of non-neuronal origin, the near-haploid knockout of DLG4 creates a clean background for investigating PSD-95 protein interactions, post-translational modifications, and signaling when components of the glutamatergic synapse are reconstituted heterologously. The absence of endogenous PSD-95 simplifies biochemical analyses, enabling unambiguous detection of exogenously expressed PSD-95 variants and binding partners. This polyclonal knockout pool is particularly suited for protein interaction network mapping by co-immunoprecipitation and proximity ligation assays, as well as for screening small molecules that disrupt or stabilize PSD-95?Creceptor complexes. It also provides an ideal negative control for immunological and proteomic studies of PSD-95 in model systems.
Researchers leverage this model to dissect the scaffolding mechanisms of PSD-95, analyze synaptic receptor trafficking in co-expression systems, and map interactomes using mass spectrometry. It supports functional assays for glutamatergic signaling when paired with NMDA or AMPA receptor constructs, facilitating the identification of modulators relevant to schizophrenia, autism, and Alzheimer’s disease. The cells are compatible with Western blotting, immunofluorescence microscopy, RT-qPCR, and flow cytometry for surface receptor detection. As an isogenic knockout resource, it also aids in validating CRISPR-Cas9 editing strategies and antibody specificity. For detailed protocols and technical support, please contact Ascent Research.
