mRNA regulation of actin binding proteins

ongoing

Cell shape is mostly controlled by the actomyosin cytoskeleton, composed of actin, myosin and multiple actin binding proteins (actin-BPs). Actin-BPs affect actin organisation and actomyosin contractility. While the mechanism of mRNA regulation of actin itself is well characterised, there is little research on the mRNA regulation of actin-BPs. Recently, the host lab discovered a novel mechanism of dose co-regulation for protein groups containing similar multivalency domains, termed interstasis. Certain actin-BPs contain multivalent C-rich regions making them a candidate protein group for mRNA regulation via interstasis. I propose to investigate the mechanism of mRNA regulation of actin-BPs, in particular those with C-rich mRNA sequences, and the possibility of feedback regulation. I will firstly identify RNA binding proteins (RNA-BPs) binding and regulating mRNAs of actin-BPs among RNA-BPs previously detected at the actin cortex and cell protrusions. I will specifically focus on identifying RNA-BPs binding to C-rich actin-BP mRNAs. I will identify the mechanism of action of these RNA-BPs via ribosome profiling, iCLIP, and smFISH. In the second part of the project, I will investigate whether C-rich actin-BPs mRNAs can be co-regulated and a potential feedback mechanism. In particular, I will use combinatory multivalency reporter to ask whether actin-BPs can be co-regulated via interstasis. Finally, I will connect mRNA regulation of actin-BPs to the actin organisation and processes affected by changes in actin organisation such as cell division and migration. To this aim, I will modulate the levels of RNA-BPs and actin-BP mRNAs and use microscopy to image the effects on the actin-driven processes. Together, I aim to further unveil molecular regulation of the actin networks during division and migration.