Background: BAF (BANF1) is a highly conserved essential protein that binds nuclear lamina proteins and DNA. Results: Perturbing BAF phosphorylation results in nuclear envelope defects and impaired cell cycle progression. Conclusion: Correct regulation of BAF phosphorylation is essential for its cellular function. Significance: The phenotype resulting from perturbing BAF phosphorylation is strikingly similar to that of a progeroid syndrome resulting from a point mutation in BAF.

). † Equal contributors to this work. SummaryDevelopment and organogenesis in both dicot and monocot plants are highly dependent on polar auxin transport (PAT), which requires the proper asymmetric localization of both auxin influx and efflux carriers. In the model dicot plant Arabidopsis thaliana, the trafficking and localization of auxin efflux facilitators such as PIN-FORMED1 (PIN1) are mediated by GNOM, a guanine-nucleotide exchange factor (GEF) for the ADPribosylation factor (ARF) family of small GTPases, but molecular regulators of the auxin influx facilitators remain unknown. Here, we show that over-expression of OsAGAP, an ARF-GTPase-activating protein (ARF-GAP) in rice, impaired PAT and interfered with both primary and lateral root development. The lateral root phenotype could be rescued by the membrane-permeable auxin 1-naphthyl acetic acid, but not by indole 3-acetic acid (IAA) or by 2,4-dichloro-phenoxyacetic acid, which require influx facilitators to enter the cells. OsAGAP-over-expressing plants had alterations in vesicle trafficking and localization of the presumptive A. thaliana auxin-influx carrier AUX1, but not in the localization of the auxin efflux facilitators. Together, our data suggest that OsAGAP has a specific role in regulating vesicle trafficking pathways such as the auxin influx pathway, which in turn controls auxin-dependent root growth in plants.

Background: Regulation of cell surface expression and signaling activity of the calcium-sensing receptor plays an important role in human diseases. Results: A PEST-like degradation motif participates in routing of the receptor to the lysosomal pathway. Conclusion: This degradation motif regulates cell surface receptor abundance. Significance: This might be a novel mechanism that connects lysosomal degradation and regulation of cell surface receptor expression.