Regulation of Type II Phosphatidylinositol Phosphate Kinase by Tyrosine Phosphorylation in Bovine Rod Outer Segments†

Biochemistry ◽  
2001 ◽  
Vol 40 (15) ◽  
pp. 4550-4559 ◽  
Author(s):  
Zhong Huang ◽  
Xiao Xia Guo ◽  
Sherry X. Chen ◽  
Kathleen M. Alvarez ◽  
Michael W. Bell ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Rod Outer Segments ◽  
Type Ii ◽  
Outer Segments ◽  
Phosphatidylinositol Phosphate ◽  
Phosphatidylinositol Phosphate Kinase

scholarly journals Tyrosine phosphorylation of type Iγ phosphatidylinositol phosphate kinase by Src regulates an integrin–talin switch

2003 ◽  
Vol 163 (6) ◽  
pp. 1339-1349 ◽  
Author(s):  
Kun Ling ◽  
Renee L. Doughman ◽  
Vidhya V. Iyer ◽  
Ari J. Firestone ◽  
Shawn F. Bairstow ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Focal Adhesions ◽  
Fold Increase ◽  
Signaling Proteins ◽  
Integrin Receptors ◽  
Dynamic Regulation ◽  
Phosphatidylinositol Phosphate ◽  
Precise Role ◽  
Phosphatidylinositol Phosphate Kinase

Engagement of integrin receptors with the extracellular matrix induces the formation of focal adhesions (FAs). Dynamic regulation of FAs is necessary for cells to polarize and migrate. Key interactions between FA scaffolding and signaling proteins are dependent on tyrosine phosphorylation. However, the precise role of tyrosine phosphorylation in FA development and maturation is poorly defined. Here, we show that phosphorylation of type Iγ phosphatidylinositol phosphate kinase (PIPKIγ661) on tyrosine 644 (Y644) is critical for its interaction with talin, and consequently, localization to FAs. PIPKIγ661 is specifically phosphorylated on Y644 by Src. Phosphorylation is regulated by focal adhesion kinase, which enhances the association between PIPKIγ661 and Src. The phosphorylation of Y644 results in an ∼15-fold increase in binding affinity to the talin head domain and blocks β-integrin binding to talin. This defines a novel phosphotyrosine-binding site on the talin F3 domain and a “molecular switch” for talin binding between PIPKIγ661 and β-integrin that may regulate dynamic FA turnover.

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