Nuclear Pore Complexes in Various States of HL-60/S4 Cells.

This study is focused upon how the structure and function of interphase nuclear pore complexes (NPCs) respond to various cellular stresses (i.e., cell differentiation, knockdown of Lamin B Receptor [LBR], and cellular dehydration) in a myeloid cell line (HL-60/S4). Each cellular stress was examined by GSEA (Gene Set Enrichment Analysis) to determine how the structure and function of the NPCs were affected. Cell differentiation into granulocytes and into macrophages resulted in widespread decreases in nucleoporin (NUP) transcription levels, affecting NPC structure and NPC transport capability. LBR knockdown (HL-60/sh1 cells) in undifferentiated cells exhibited major increases in NUP transcription, combined with improved NPC structural quality and transport capability, implying that nuclear pore function is not adversely affected by the loss of LBR. In contrast, cell dehydration of the undifferentiated HL-60/S4 cells in hyperosmotic culture medium resulted in disorganized nucleoporin transcription, with evidence of abnormal NPC structure and transport capability. The structural integrity and transport function of nuclear pores are clearly responsive to the various cellular stresses. Future investigations should examine the reversibility and resilience of these cells to such stresses as those described in this study.