ABSTRACT
Lamins are intermediate filament proteins that contribute to numerous cellular functions, including nuclear morphology and mechanical stability. The N-terminal head domain of lamin is crucial for higher order filament assembly and function, yet the effects of commonly used N-terminal tags on lamin function remain largely unexplored. Here, we systematically studied the effect of two differently sized tags on lamin A (LaA) function in a mammalian cell model engineered to allow for precise control of expression of tagged lamin proteins. Untagged, FLAG-tagged and GFP-tagged LaA completely rescued nuclear shape defects when expressed at similar levels in lamin A/C-deficient (Lmna–/–) MEFs, and all LaA constructs prevented increased nuclear envelope ruptures in these cells. N-terminal tags, however, altered the nuclear localization of LaA and impaired the ability of LaA to restore nuclear deformability and to recruit emerin to the nuclear membrane in Lmna–/– MEFs. Our finding that tags impede some LaA functions but not others might explain the partial loss of function phenotypes when tagged lamins are expressed in model organisms and should caution researchers using tagged lamins to study the nucleus.
Footnotes
Author contributions
Conceptualization: J.O., J.L.; Methodology: J.O.; Formal analysis: J.O.; Investigation: J.O.; Writing - original draft: J.O., J.L.; Writing - review & editing: J.O., J.L.; Project administration: J.L.; Funding acquisition: J.L.
Funding
This work was supported by awards from the Volkswagen Foundation (A130142 to J.L.), the National Institutes of Health (R01 HL082792, R01 GM137605 and R35 GM153257 to J.L.), and the National Science Foundation (URoL2022048 to J.L.). The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Deposited in PMC for release after 12 months.
Data availability
All relevant data can be found within the article and its supplementary information.
