Girdin Proteins and Enzymes

Girdin (GIRDers of actIN filaments; also APE and GIV) is a member of the CCDC88 family of molecules. It is a cytosolic protein, ubiquitously expressed, and plays a key role in the motility of breast cancer cells. Human Girdin is 1871 amino acids (aa) in length. It contains two coiled-coil regions that mediate homodimerization (aa 196-425 and 458-1358), and one phosphoinositide-binding domain (aa 1390-1408). Normally, Girdin is membrane-associated via an interaction with phosphoinositides. Upon phosphorylation at Ser1417 by Akt, it relocates to lamellipodia where it crosslinks actin filaments. Multiple isoforms of Girdin have been detected.