Targeted protein relocalization via protein transport coupling

Abstract

Subcellular protein localization regulates protein function and can be corrupted in cancers1 and neurodegenerative diseases2,3. The rewiring of localization to address disease-driving phenotypes would be an attractive targeted therapeutic approach. Molecules that harness the trafficking of a shuttle protein to control the subcellular localization of a target protein could enforce targeted protein relocalization and rewire the interactome. Here we identify a collection of shuttle proteins with potent ligands amenable to incorporation into targeted relocalization-activating molecules (TRAMs), and use these to relocalize endogenous proteins. Using a custom imaging analysis pipeline, we show that protein steady-state localization can be modulated through molecular coupling to shuttle proteins containing sufficiently strong localization sequences and expressed in the necessary abundance. We analyse the TRAM-induced relocalization of different proteins and then use nuclear hormone receptors as shuttles to redistribute disease-driving mutant proteins such as SMARCB1Q318X, TDP43ΔNLS and FUSR495X. TRAM-mediated relocalization of FUSR495X to the nucleus from the cytoplasm correlated with a reduction in the number of stress granules in a model of cellular stress. With methionyl aminopeptidase 2 and poly(ADP-ribose) polymerase 1 as endogenous cytoplasmic and nuclear shuttles, respectively, we demonstrate relocalization of endogenous PRMT9, SOS1 and FKBP12. Small-molecule-mediated redistribution of nicotinamide nucleotide adenylyltransferase 1 from nuclei to axons in primary neurons was able to slow axonal degeneration and pharmacologically mimic the genetic WldS gain-of-function phenotype in mice resistant to certain types of neurodegeneration4. The concept of targeted protein relocalization could therefore inspire approaches for treating disease through interactome rewiring. Targeted protein relocalization using shuttle proteins with potent ligands amenable to incorporation into targeted relocalization activating molecules could be used to regulate cellular physiology and correct disease states in neurodegenerative diseases, cancer and genetic disorders.