A proximity-labeling map of PI5P4K phosphoinositide kinases interaction networks

Phosphatidylinositol-5-phosphate 4-kinases (PI5P4Ks) have emerged as candidate drug targets in cancer, neurological, inflammatory, and infectious diseases. Although their canonical function is to phosphorylate PI(5)P to generate PI(4,5)P₂, growing evidence points to additional catalytic-independent roles, but how these functions are organized within protein interaction networks remains unclear. Here, we use proximity-dependent biotin identification (BioID) in HeLa cells to map isoform-resolved interactomes of human PI5P4Kα, PI5P4Kβ, and PI5P4Kγ. This approach captures PI5P4K-proximal proteins in intact cells and reveals interaction networks positioning these kinases within trafficking-associated signaling modules. Importantly, BioID analysis indicates that PI5P4Kγ has the most extensive set of proximal interactors among the three PI5P4Ks, consistent with its comparatively low catalytic activity and a prominent scaffold-like function. Among PI5P4Kγ-enriched partners, we highlight the endosomal cargo adaptor SNX17 as a proximal interactor that links PI5P4Kγ to β1-integrin recycling and to cell migration and invasion. By providing a proximity map for all three PI5P4Ks, this study offers a framework to help define contexts in which targeted protein degradation may offer advantages over catalytic inhibition and provides a resource for future mechanistic studies on these phosphoinositide kinases.