You can query QuickGO using a number of different identifier types (including: DictyBase, UniGene, UniProtKB, FlyBase, Gramene, Mouse Genome Informatics, GeneDB (S. Pombe), The Institute of Genome Research, WormBase, The Zebrafish Information Network, Ensembl, NCBI Reference Sequences, EMBL accession and NCBI Entrez Gene identifiers).
You can enter a single identifier into the search box on QuickGO's home page (or in the header on other pages) to retrieve the matching UniProt accession and link to its annotations.