Protein Domain : Type VI secretion system TssC IPR035576

Type	Family
Description	TssC (also known as VipB) is a family of Gram-negative type VI secretion system components of the tail sheath. They have been known as COG3517. These sheath-components, of which there are many copies in the sheath, are also variously referred to as TssC. On contact with another bacterial cell the sheath contracts and pushes the puncturing device and tube through the cell envelope and punches the target bacterial cell []. VipA and VipB (TssB and TssC) proteins were shown to form a cog-wheel like tubular structure in V. cholerae that was noticed to resemble T4 phage gp18 polysheath. Two β-strands of VipA and four β-strands of VipB intertwine forming the middle layer of the sheath. The sheath assembles around an inner Hcp tube and is attached to a structure called a baseplate that spans the bacterial membranes. Importantly, VipA/VipB sheath was shown to form a long contractile organelle in V. cholerae and in E. coli, suggesting that sheath contraction powers the secretion [].This entry includes TssC mostly from Bacteroidetes. The type VI secretion system (T6SS) is a supra-molecular bacterial complex that resembles phage tails. It is a toxin delivery systems which fires toxins into target cells upon contraction of its TssBC sheath [ ]. Thirteen essential core proteins are conserved in all T6SSs: the membrane associated complex TssJ-TssL-TssM, the baseplate proteins TssE, TssF, TssG, and TssK, the bacteriophage-related puncturing complex composed of the tube (Hcp), the tip/puncturing device VgrG, and the contractile sheath structure (TssB and TssC). Finally, the starfish-shaped dodecameric protein, TssA, limits contractile sheath polymerization at its distal part when TagA captures TssA [].
Short Name	T6SS_TssC