Neural stem cell interkinetic nuclear migration is controlled by a phosphatidylinositol transfer protein/non-canonical planar cell polarity signaling axis

Speaker: Professor Vytas Bankaitis – Texas A&M University, United States

Abstract: The mammalian neocortex rapidly expands during embryonic development, and complexity of the neocortex is correlated with apre dominant expansion in its lateral dimension so that the neocortical surface area is increased. By contrast, expansion in the radial dimension is restricted via unknown mechanisms. I will discuss our recent progress in addressing this question. We find that the signature interkinetic nuclear migration (IKNM) of embryonic neural stem cells (NSCs) relies on a phosphatidylinositol transfer protein (PITP)-noncanonical planar cell polarity (ncPCP) signaling axis that controls radial expansion of the developing neocortex. Those PITP-dependent perturbations in IKNM and neocortical morphogenesis were reproduced in two other experimental systems: (i) in mouse embryos ablated for either of two ncPCP receptor gene activities, and (ii) in a models where individual NSCs express a dominant-negative variant of a third ncPCP receptor in an otherwise wild-type neurogenic niche. PITP signaling is coupled to ncPCP pathway activity on the basis of its potentiation export of a subset of ncPCP receptors from the trans-Golgi network to the NSC cell surface. Our data identify IKNM as a driving force for a special form of convergent extension that integrates PITP-mediated phosphoinositide signaling with the activity of the evolutionarily conserved ncPCP pathway.

Speaker profile: Vytas Bankaitis is a University Distinguished Professor at the Department of Molecular & Cellular Medicine, Texas A&M University Health Sciences Center.

Prof Bankaitis served on numerous NIH, NSF, NCI, American Heart Association and American Cancer Society panels (national and regional) grant review/center review/program project review panels as permanent or ad hoc member – including having served as Chairman of the NIH CDF-2 and MMBP Initial Review Groups.

In terms of administration, he served as Chair of the Dept. of Cell & Developmental Biology at the UNC School of Medicine for 11 years where he spearheaded implementation of a problem-oriented graduate curriculum, and administrated a complete and highly successful overhaul of the Anatomy and Histology courses for medical students.

He is an active member of the EMBO Reports, Chemistry & Physics of Lipids, and Methods Editorial Boards, and a past member of the Faculty of 1000, Membrane Trafficking and Sorting Section. He is also currently organizing and editing a Special Issue on Phosphoinositides for the Journal of Lipid Research.

He served as Vice-Chair (2009) and Chair (2011) for the Signal Transduction Within the Nucleus Gordon Research Conferences, was Member of the Program Planning Committee for the American Society for Biochemistry and Molecular Biology (ASBMB) Annual Meeting (2011), developed a mini-symposium at the American Society of Cell Biology Annual Meeting (2012), and co-chaired the FASEB Conference on Phospholipid Metabolism (2012). He also served as Director of the ASBMB Lipid Research Division from 2013-2017.

His life’s work defining challenge led to understanding the ‘problem’ of how lipid signaling is physically organized and regulated on membrane surfaces - specifically, how phosphatidylinositol (PtdIns) transfer proteins (PITPs) determine these parameters at physiological, cell biological and single molecule levels.

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