The SH2 Domain of the Src Family Kinase FYN Binds to Partitioning Defective Protein 3 (PARD3)

Abstract

The Src Family of tyrosine Kinases (SFKs) are activated downstream of stimulated growth factor receptors to regulate a host of cellular processes including proliferation, migration, and survival. Aberrantly regulated SFKs are implicated in a variety of cancers, making the study of their regulation important. Using a quantitative mass spectrometry (SILAC) approach in HEK293 cells, we identified a novel SFK binding partner, partition defective 3 (PARD3), a protein known to regulate epithelial cell polarity. PARD3 is known to be phosphorylated at pY 1127 by the SFKs SRC and YES downstream of EGF receptor signaling; however, binding of SFKs to PARD3 has not previously been reported. The goal of this study was to validate and further characterize PARD3‐SFK binding. Pulldown experiments using GST‐SH2 fusion constructs for the SFK FYN with HEK293 cell extracts followed by immunoblotting for PARD3 confirmed that PARD3 binds to FYN's SH2 domain. ScanSite and PhosphoSite analysis were used to predict specific phosphotyrosine residues in PARD3 that may be responsible for FYN SH2‐PARD3 binding. This study suggests that SFK signaling regulates PARD3 function.Support or Funding InformationResearch reported in this project was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103449. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIGMS or NIH.