phosphatidylinositol-4-phosphate 3-kinase C2 domain-containing beta (PIK3C2B)

Function

• phosphorylates PtdIns & PtdIns4P, preference for PtdIns
• does not phosphorylate PtdIns(4,5)P2.
• may be involved in EGF & PDGF signaling
• part of a complex with ERBB2 & EGFR
• part of a complex with phosphorylated EGFR & GRB2
• interacts with phosphorylated EGFR & PDGFR, maybe indirectly
• interacts with GRB2 & SHC1
• activated by GRB2

ATP + 1-phosphatidyl-1D-myo-inositol 4-phosphate
                   <-->
ADP + 1-phosphatidyl-1D-myo-inositol 3,4-bisphosphate

Cofactor: Ca+2, Mg+2, or Mn+2

Structure

• belongs to the PI3/PI4-kinase family
• contains 1 C2 domain
• contains 1 PI3K/PI4K domain
• contains 1 PX (phox homology) domain

Compartment

• microsome, cell membrane. cytoplasm
• found mostly in the microsome, but also in plasma membrane & cytosol
• nuclear in testis

Expression

• expressed in columnar & transitional epithelia, mononuclear cells, & ganglion cells (at protein level)
• widely expressed
• highest levels in thymus & placenta
• lowest leverls in peripheral blood, skeletal muscle & kidney

Notes

uncertain whether Met-1 or Met-26 is the initiator

More general terms

• phosphatidylinositol-4-phosphate 3-kinase

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5287
• OMIM: https://mirror.omim.org/entry/602838
• UniProt: http://www.uniprot.org/uniprot/O00750.html