Fig. 2.

Versatile signaling actions of mammalian IPMK.

As a PI3-kinase, IPMK activates Akt signaling. Water-soluble, inositol phosphates produced from IPMK such as Ins(1,4,5,6)P₄ appears essential for class I HDAC function. Independent of its catalytic activity, IPMK directly binds to various cytosolic signaling factors, thereby regulating multiple signaling networks. Inside the nucleus, IPMK is a key node of molecular events (e.g., selective mRNA export, transcription). It acts as a transcription coactivator via forming complexes with transcription factors as well as epigenetic regulators. See main text for further details. Blue lines indicate catalytic activity-dependent IPMK actions. Red lines designate IPMK-binding partners which are non-catalytically regulated by IPMK.