Phosphorylates PtdIns and PtdIns4P with a preference for PtdIns (PubMed:10805725, PubMed:11533253, PubMed:9830063). Does not phosphorylate PtdIns(4,5)P2 (PubMed:9830063). May be involved in EGF and PDGF signaling cascades (PubMed:10805725). {ECO:0000269|PubMed:10805725, ECO:0000269|PubMed:11533253, ECO:0000269|PubMed:9830063}. This is the function of PIK3C2B (phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2 beta, Ensembl gene identifier ENSG00000133056).