Converts inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) to inositol 1,4-bisphosphate. Modulates cotyledon vein development through regulating auxin homeostasis. Involved in blue light responses. Decreases the amount of KIN10 degraded by the proteasome under low nutrient conditions. Participates with IP5P12 in the control of Ins(1,4,5)P3/Ca(2+) levels that is crucial for maintaining pollen dormancy and regulating early germination of pollen. May modulate auxin transport by regulating vesicle trafficking and thereby plays a role in root gravitropism. 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate Interacts with KIN10, but not with PHOT1. Expressed in young seedlings and flowers. Highly expressed in anther and pollen grains, but not in pistils. Not detected in maturated roots, stems and rosette leaves. Detected in cotyledons prior to seed germination. Restricted to the cotyledon tip until 2 days after seed germination and then detected in the cotyledon or cotyledon veins on days 3 to 7. By abscisic acid, wounding and at a lower level, by cold and salt treatment. Down-regulated by blue light irradiation. The WD40 domain (1-533) is interacting with KIN10. Defect in development of the cotyledon veins. Altered auxin homeostasis and reduced abscisic acid sensitivity. Shortened hypocotyls and expanded cotyledons in response to blue light irradiation. Precocious pollen germination within anthers. Elevated sensitivity to gravistimulation in root gravitropic responses. Belongs to the inositol polyphosphate 5-phosphatase family.