Component of a heteromeric calcium-permeable ion channel formed by PKD1 and PKD2 that is activated by interaction between PKD1 and a Wnt family member, such as WNT3A and WNT9B (PubMed:27214281). Both PKD1 and PKD2 are required for channel activity (PubMed:27214281). Involved in renal tubulogenesis (PubMed:12482949). Involved in fluid- flow mechanosensation by the primary cilium in renal epithelium (By similarity). Acts as a regulator of cilium length, together with PKD2 (By similarity). The dynamic control of cilium length is essential in the regulation of mechanotransductive signaling (By similarity). The cilium length response creates a negative feedback loop whereby fluid shear-mediated deflection of the primary cilium, which decreases intracellular cAMP, leads to cilium shortening and thus decreases flow- induced signaling (By similarity). May be an ion-channel regulator. Involved in adhesive protein-protein and protein-carbohydrate interactions. Likely to be involved with polycystin-1-interacting protein 1 in the detection, sequestration and exocytosis of senescent mitochondria (PubMed:37681898). {ECO:0000250|UniProtKB:O08852, ECO:0000269|PubMed:12482949, ECO:0000269|PubMed:27214281, ECO:0000269|PubMed:37681898}. [Isoform 4]: Plays a role in mitochondrial dynamics. In immortalized renal cyst cells, converts fragmented mitochondria to a filamentous shape. . This is the function of PKD1 (polycystin 1, transient receptor potential channel interacting, Ensembl gene identifier ENSG00000008710).