Component of the SSU processome, a pre-ribosomal particle required for the maturation of the 18S rRNA from the 35S pre-rRNA precursor. Component of the ribosomal small subunit (SSU) processome, or 90S pre-ribosomal particle, composed of the 35S pre-rRNA precursor, the U3 snoRNA, and at least 40 protein subunits. Component of the PWP2/UTP-B subcomplex composed of DIP2, PWP2, UTP6, UTP13, UTP18 and UTP21. Interacts with U3 snoRNA. Interacts with MPP10. Present with 7520 molecules/cell in log phase SD medium. Belongs to the UTP6 family.