Structural basis of membrane targeting by the Phox homology domain of cytokine-independent survival kinase (CISK-PX)
Xing, Y., Liu, D., Zhang, R., Joachimiak, A., Songyang, Z., Xu, W.(2004) J Biol Chem 279: 30662-30669
- PubMed: 15126499 
- DOI: https://doi.org/10.1074/jbc.M404107200
- Primary Citation of Related Structures:  
1XTE, 1XTN - PubMed Abstract: 
The cytokine-independent survival kinase (CISK) in the serum and glucocorticoid-regulated kinase family plays an important role in mediating cell growth and survival. N-terminal to its catalytic kinase domain, CISK contains a phox homology (PX) domain, a phosphoinositide-binding motif that directs the membrane localization of CISK and regulates CISK activity. We have determined the crystal structures of the mouse CISK-PX domain to unravel the structural basis of membrane targeting of CISK. In addition to the specific interactions conferred by the phosphoinositide-binding pocket, the structure suggests that a hydrophobic loop region and a hydrophilic beta-turn contribute to the interactions with the membrane. Furthermore, biochemical studies reveal that CISK-PX dimerizes in the presence of the linker between the PX domain and kinase domain, suggesting a multivalent mechanism in membrane localization of CISK.
Organizational Affiliation: 
Department of Biological Structure, University of Washington, Seattle, Washington 98195-7420, USA.