Presumably involved in the export of the biofilm adhesin polysaccharide poly-beta-1,6-N-acetyl-D-glucosamine (PNAG, also referred to as PIA) across the cell membrane. Deletion of the icaADBCR genes leads to the inability to form biofilms, produce PIA or mediate N-acetylglucosaminyltransferase activity in vitro. Belongs to the acyltransferase 3 family.