Cellulose synthase catalytic subunit A2 (CESA2) is a catalytic subunit or a catalytic subunit substitute of the cellulose synthase complex.
Cellulose synthase (CESA) catalyzes the polymerization reaction of cellulose using UDP-glucose as the substrate. Cellulose is an aggregate of unbranched polymers of beta-1,4-linked glucose residues, which is an abundant polysaccharide produced by plants and in varying degrees by several other organisms including algae, bacteria, fungi, and even some animals. Genomes from higher plants harbor multiple CESA genes. There are ten in Arabidopsis. At least three different CESA proteins are required to form a functional complex. In Arabidopsis, CESA1, 3 and 6 and CESA4, 7 and 8, are required for cellulose biosynthesis during primary and secondary cell wall formation. CESA2 is very closely related to CESA6 and is viewed as a prime substitute for CESA6. They functionally compensate each other. The cesa2 and cesa6 double mutant plants were significantly smaller, while the single mutant plants were almost normal.