Integration of cell polarity, cell geometry and phospho-regulation at the division site of plants

01/06/2018 to 31/05/2021

Plant cells are confined by cellulosic walls which fix them in position
and determine their cell shapes. Therefore, spatio-temporal regulation
of division planes are critical for cell shape and consequently plant
morphology. In plant cells the division plane is established in
prophase by the plant specific cytoskeletal preprophase band, whose
position becomes the site of cell plate fusion later in cytokinesis. The
motor proteins Kinesin-12 POK1 and POK2 are key components
required for division site maintenance and for the guidance of the
cytokinetic apparatus, termed phragmoplast. However, their
interaction partners RhoGAP are involved in division site selection
and subsequent POK1 positioning. The selection of the division site is
influenced by cell polarity and cell geometry. How this information is
translated into a RhoGAP-dependent selection of the division site by
the cell is unclear. We will take advantage of our mutants (phgaps,
poks), and use 3-dimensional(D) and 4-D imaging confocal
microscopy and image processing using dedicated software (ImageJ,
MorphographX), to investigate how cell geometry and cell polarity
influence molecular establishment of the future division site. In
addition we will investigate how phospho-regulation affects
localization, activity and binding affinities of division site markers
POK1/2 and TANGLED.