Slingshot protein

Slingshot 1 is a member of slingshot (SSH) family of protein phosphatases; it is located at human chromosome 12q24.11. Slingshot is one of the primary dedicated cofilin phosphatases. It plays an important role in cell migration by dephosphorylating cofilin at Ser3 and activating it in a variety of cell types such as keratinocytes and aortic smooth muscle cells (1). Slingshot (SSH) activity can be modulated by F-actin binding, calcium acting via calcinerium, and by its association in inhibitory complexes with 14-3-3 regulatory proteins (2). 14-3-3zeta/tau heterodimers are key regulators of slingshot 1 isoform 1 (SSH1) activity in keratinocytes (3). SSH1 is involved in H₂O₂ induced cofilin dephosphorylation and activation. Such activation of SSH1-cofilin pathway stimulates the SSH1 dependent formation of cofilin-actin rods in HeLa cells (4). By dephosphorylating and activating cofilin, SSH1 plays a critical role in insulin-induced membrane protrusion and cytokinesis.

SSH1 has the SSH family-specific, N-terminal, noncatalytic (SSH-N) domain. This domain has been shown to play critical roles in P-cofilin recognition, F-actin-mediated activation, and subcellular localization of SSH1 (5). Recently it was shown that expression of phosphatase-dead versions of SSH proteins resulted in phosphorylation/inactivation of cofilin, changes in cytoskeleton organization, loss of cell polarity, and assembly of aberrant arrays of laminin-332 in human keratinocytes (6). SSH1 mutations were seen in patients with disseminated superficial actinic porokeratosis. SSH1 is expressed in a various cell types including keratinocytes, HeLa cells and smooth muscle cells. It is approximately a 126kDa protein (1049 amino acids).

The SSH1-selective antibodies were generated against purified Slingshot1 isoform1 (SSH1) protein. SSH1-antibodies are affinity purified over immobilized antigen based chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer. FabGennix Int. Inc. will also provide limited quantities of antigenic blocking protein for SISHT -101AP antibody. Antibodies to SSH1 (SISHT-101AP) will label ~126kDa protein in Western blot positive control samples for SSH1 and several other tissues. FabGennix Inc. will also conjugate antibodies with secondary enzymes (alk-Pase or HRP) or fluorescent probes upon request at nominal cost.