Slingshot Homolog 2 (SSH2)

Two of the human proteins, SSH1L and SSH2, were enzymatically active when reacted with an artificial substrate, p-nitrophenyl phosphate. SSH3 did not exhibit activity toward p-nitrophenyl phosphate, and its expression did not reduce the level of P-cofilin in COS-7 cells. In mammalian cells, SSH1L and SSH2 suppressed LIMK1-induced actin reorganization. Furthermore, ssh, SSH1L, and SSH2 dephosphorylated P-cofilin in cultured cells and in cell-free assays. SSH1 encodes 3 isoforms, SSH1L, SSH1S, and SSH1B, and SSH2 encodes 2 isoforms, SSH2 and SSH2B. The SSH3 protein has 471 amino acids. Besides the catalytic domain, 2 other domains are conserved between Drosophila ssh and the human SSHs (domains A and B) and are unique to the SSH family.