Essential for cellulose biosynthesis, shown for strain 1094, a commensal, natural cellulose producer (PubMed:19400787). Also shown in strain W3110 which has a restored reading frame (TAG stop codon to TTG for amino acid 6, called strain AR3110) (PubMed:24097954, this protein). May play a role in subcellular localization of an active cellulose biosynthesis apparatus at the bacterial cell pole (PubMed:19400787). The combination of cellulose and the curli fiber network confer cohesion, elasticity and tissue-like properties to colonies (PubMed:24097954). Localizes at the cell pole, this does not require any genes of the divergently expressed yhjRbcsQABZC and bcsEFG operons. Part of the yhjR-bcsQABZC operon (PubMed:19400787, PubMed:24097954). Expressed at low levels in mid-log phase, expression increases as cells enter stationary phase, the increase in stationary phase is dependent on rpoS (PubMed:24097954). In K12 strains the premature stop codon in position 8 has polar effects on downstream genes, decreasing their expression about 10-fold (PubMed:24097954). The N-terminal putative ATP-binding domain is required for function. The C-terminal region contributes to both localization and function in cellulose synthesis. Deletion abolishes cellulose production. Cellulose production is abolished in E.coli K12 / MG1655 and W3110 due to a premature stop codon in bcsQ. The C-terminal pseudogene prediction is found here (AC P37655) (PubMed:24097954). Belongs to the BcsQ family.