LRRC59 is a leucine-rich repeat-containing protein that functions as a multifaceted regulator of cellular processes. Its primary function involves facilitating nuclear import of FGF1 through interaction with karyopherin-α1 and karyopherin-β1, while being dispensable for FGF2 nuclear import 1. LRRC59 localizes to the endoplasmic reticulum (ER) and nuclear envelope through post-translational membrane insertion, with its targeting to the inner nuclear membrane governed by passive diffusion rather than classic nuclear transport machinery 2. The protein plays a critical role in ER-localized mRNA translation regulation, with LRRC59 depletion reducing steady-state translation levels on the ER by approximately 50% 3. Additionally, LRRC59 serves as a positive regulator of DDX58/RIG-I-mediated type I interferon signaling by blocking the autophagic degradation of DDX58, thereby enhancing antiviral immune responses 4. The protein also functions in nuclear envelope repair by cooperating with nuclear transporters to regulate LEMD2-CHMP7 complex assembly and prevent genome instability 5. In cancer contexts, LRRC59 promotes oncogenic processes including cell proliferation, migration, and invasion while inhibiting PERK pathway-induced apoptosis 67.