The function of PKP3 (plakophilin 3, Ensembl gene identifier ENSG00000184363) is as follows. A component of desmosome cell-cell junctions which are required for positive regulation of cellular adhesion (PubMed:24124604). Required for the localization of DSG2, DSP and PKP2 to mature desmosome junctions (PubMed:20859650). May also play a role in the maintenance of DSG3 protein abundance in keratinocytes (By similarity). Required for the formation of DSP-containing desmosome precursors in the cytoplasm during desmosome assembly (PubMed:25208567). Also regulates the accumulation of CDH1 to mature desmosome junctions, via cAMP-dependent signaling and its interaction with activated RAP1A (PubMed:25208567). Positively regulates the stabilization of PKP2 mRNA and therefore protein abundance, via its interaction with FXR1, may also regulate the protein abundance of DSP via the same mechanism (PubMed:25225333). May also regulate the protein abundance of the desmosome component PKP1 (By similarity). Required for the organization of desmosome junctions at intercellular borders between basal keratinocytes of the epidermis, as a result plays a role in maintenance of the dermal barrier and regulation of the dermal inflammatory response (By similarity). Required during epidermal keratinocyte differentiation for cell adherence at tricellular cell- cell contacts, via regulation of the timely formation of adherens junctions and desmosomes in a calcium-dependent manner, and may also play a role in the organization of the intracellular actin fiber belt (By similarity). Acts as a negative regulator of the inflammatory response in hematopoietic cells of the skin and intestine, via modulation of proinflammatory cytokine production (By similarity). Important for epithelial barrier maintenance in the intestine to reduce intestinal permeability, thereby plays a role in protection from intestinal-derived endotoxemia (By similarity). Required for the development of hair follicles, via a role in the regulation of inner root sheaf length, correct alignment and anterior-posterior polarity of hair follicles (By similarity). Promotes proliferation and cell-cycle G1/S phase transition of keratinocytes (By similarity). Promotes E2F1- driven transcription of G1/S phase promoting genes by acting to release E2F1 from its inhibitory interaction with RB1, via sequestering RB1 and CDKN1A to the cytoplasm and thereby increasing CDK4- and CDK6-driven phosphorylation of RB1 (By similarity). May act as a scaffold protein to facilitate MAPK phosphorylation of RPS6KA protein family members and subsequently promote downstream EGFR signaling (By similarity). May play a role in the positive regulation of transcription of Wnt-mediated TCF-responsive target genes (PubMed:34058472). {ECO:0000250|UniProtKB:Q9QY23, ECO:0000269|PubMed:20859650, ECO:0000269|PubMed:24124604, ECO:0000269|PubMed:25208567, ECO:0000269|PubMed:25225333, ECO:0000269|PubMed:34058472}.