Function
Serine/threonine-protein kinase involved in the regulation of auxin signaling. Acts as a positive regulator of cellular auxin efflux and regulates organ development by enhancing polar auxin transport. Phosphorylates conserved serine residues in the PIN auxin efflux carriers. Phosphorylation of PIN proteins is required and sufficient for apical-basal PIN polarity that enables directional intercellular auxin fluxes, which mediate differential growth, tissue patterning and organogenesis. Acts in association with PIN1 to control the establishment of bilateral symmetry and promotion of cotyledon outgrowth. Regulates root gravitropism through modulation of PIN2-dependent basipetal auxin transport. Required for polarization of PIN3-dependent auxin transport for hypocotyl gravitropic response. The protein kinase activity of PID is essential for its auxin efflux regulatory function. PID kinase and PP2A phosphatase activities antagonistically regulate phosphorylation of PIN proteins, affecting PIN sorting.
Sequence
MLRESDGEMSLGTTNSPISSGTESCSSFSRLSFDAPPSTIPEEESFLSLKPHRSSDFAYAEIRRRKKQGLTFRDFRLMRRIGAGDIGTVYLCRLAGDEEESRSSYFAMKVVDKEALALKKKMHRAEMEKTILKMLDHPFLPTLYAEFEASHFSCIVMEYCSGGDLHSLRHRQPHRRFSLSSARFYAAEVLVALEYLHMLGIIYRDLKPENILVRSDGHIMLSDFDLSLCSDSIAAVESSSSSPENQQLRSPRRFTRLARLFQRVLRSKKVQTLEPTRLFVAEPVTARSGSFVGTHEYVAPEVASGGSHGNAVDWWAFGVFLYEMIYGKTPFVAPTNDVILRNIVKRQLSFPTDSPATMFELHARNLISGLLNKDPTKRLGSRRGAAEVKVHPFFKGLNFALIRTLTPPEIPSSVVKKPMKSATFSGRSSNKPAAFDYF