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Nuclear Phosphoinositides

Current open questions regarding nuclear PIP-kinases

To date most studies on PI-mediated cellular functions and processes have focused on cytosolic, vesicular, ER-associated and/or plasma membrane-located PIs, both in mammalian and plant models. However, over the past years more and more evidence emerges indicating functions of PIs also in the nucleus. Nuclear processes that are likely influenced by PIs include DNA repair, transcriptional regulation, mRNA processing as well as chromatin remodeling and cell cycle control. It is unclear how PIs are involved in these processes. Current data suggest that the nucleus contains a PI system that holds the same enzymes for the generation and modification of PIs that are known also from other cellular compartments. In fact, some PI-modifying enzymes appear to be able to act both inside and outside the nucleus and to fulfill different functions in both locations. Therefore, the subcellular distribution of such enzymes must be tightly regulated.

It is the goal of our studies to identify the key enzymes responsible for the formation and degradation of PIs in the nucleus of plant cells. Moreover, we aim to elucidate the regulation of their nuclear import and to identify nuclear targets of PI-regulation. To reach these goals, we are employing experiments combining genetic, physiological, cell biological and in vitro-biochemical techniques.

• Supported by the DFG Research Training Group RTG2498 (project P10)

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