Related Experiment Video
Updated: Aug 8, 2026

PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions
Published on: July 27, 2017
Regulation of the interaction between PIPKI gamma and talin by proline-directed protein kinases
Sang Yoon Lee1, Sergey Voronov, Kresimir Letinic
1Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
Abstract:
The interaction of talin with phosphatidylinositol(4) phosphate 5 kinase type I gamma (PIPKI gamma) regulates PI(4,5)P2 synthesis at synapses and at focal adhesions. Here, we show that phosphorylation of serine 650 (S650) within the talin-binding sequence of human PIPKI gamma blocks this interaction. At synapses, S650 is phosphorylated by p35/Cdk5 and mitogen-activated protein kinase at rest, and dephosphorylated by calcineurin upon stimulation. S650 is also a substrate for cyclin B1/Cdk1 and its phosphorylation in mitosis correlates with focal adhesion disassembly. Phosphorylation by Src of the tyrosine adjacent to S650 (Y649 in human PIPKI gamma) was shown to enhance PIPKI gamma targeting to focal adhesions (Ling, K., R.L. Doughman, V.V. Iyer, A.J. Firestone, S.F. Bairstow, D.F. Mosher, M.D. Schaller, and R.A. Anderson. 2003. J. Cell Biol. 163:1339-1349). We find that Y649 phosphorylation does not stimulate directly PIPKI gamma binding to talin, but may do so indirectly by inhibiting S650 phosphorylation. Conversely, S650 phosphorylation inhibits Y649 phosphorylation by Src. The opposite effects of the phosphorylation of Y649 and S650 likely play a critical role in regulating synaptic function as well as the balance between cell adhesion and cell motility.
Related Concept Videos
Phosphoinositides and PIPs
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Mechanism of Lamellipodia Formation
Amplifying Signals via Enzymatic Cascade
The JAK-STAT Signaling Pathway
PI3K/mTOR/AKT Signaling Pathway
Intracellular Signaling Affects Focal Adhesions
Some...

