Modifier	Substrate	Residue	Sequence	Mechanism/Effect	PMID	Interaction ID
CSNK2A1	PIK3R1	Ser608 View in OncoXplorer	ENTEDQYsLVEDDED	phosphorylation up-regulates activity	14729945	SIGNOR-276005
PPM1A	PIK3R1	Ser608 View in OncoXplorer	ENTEDQYsLVEDDED	dephosphorylation up-regulates activity	15016818	SIGNOR-248489
PIK3CA	PIK3R1	Ser608 View in OncoXplorer	ENTEDQYsLVEDDED	phosphorylation up-regulates activity	14729945	SIGNOR-276004

Enzyme	Effect	Phosphosite	Effect	Target	PMID	Interaction ID
CSNK2A1	phosphorylation up-regulates →	PIK3R1 PSer608	phosphorylation up-regulates →	PIK3R1	14729945	SIGNOR-276005
PPM1A	dephosphorylation down-regulates ⊣	PIK3R1 PSer608	dephosphorylation down-regulates ⊣	PIK3R1	15016818	SIGNOR-248489
PIK3CA	phosphorylation up-regulates →	PIK3R1 PSer608	phosphorylation up-regulates →	PIK3R1	14729945	SIGNOR-276004

Regulator	Mechanism/Effect	Target	SIGNOR-ID
CSNK2A1	phosphorylation → up-regulates activity	PIK3R1	SIGNOR-276005
PPM1A	dephosphorylation → up-regulates activity	PIK3R1	SIGNOR-248489
PIK3CA	phosphorylation → up-regulates activity	PIK3R1	SIGNOR-276004