The nuclear basket is a critical structure within the nuclear pore complex (NPC), playing a key role in mRNA surveillance and chromatin organization. This study uses in-cell cryo-electron tomography and subtomogram analysis to explore the structural variations of the NPC across fungi (yeast), mammals (mouse), and protozoa (Toxoplasma gondii). The research reveals that the nuclear basket consists of eight struts emanating from a double nuclear ring (NR), which terminate in a distal globular density. This density is thought to serve as a docking site for mRNA preprocessing before nucleocytoplasmic transport. The basket's architecture is stabilized by a hub of nucleoporins (Nups) in the nuclear ring, which bind to basket-forming Mlp/Tpr proteins. The coiled-coil domains of Mlp/Tpr form the struts, while their unstructured termini constitute the distal densities. The study also highlights the importance of the double NR in stabilizing the basket, as single NR variants do not support a stable basket. The basket's distal density contains the N/C termini of the strut-forming proteins, which serve as a docking platform for cargo and nuclear periphery elements. The research provides a detailed molecular architecture of the yeast and mammalian baskets, revealing their structural similarities and differences. The findings suggest that the basket's dynamic nature allows it to interact with various proteins and may have additional components beyond the identified ones. The study also discusses the functional implications of the basket's structure, including its role in chromatin organization and mRNA transport. The results highlight the importance of the NPC's structural plasticity and the need for further studies to understand the basket's role in different cellular contexts.The nuclear basket is a critical structure within the nuclear pore complex (NPC), playing a key role in mRNA surveillance and chromatin organization. This study uses in-cell cryo-electron tomography and subtomogram analysis to explore the structural variations of the NPC across fungi (yeast), mammals (mouse), and protozoa (Toxoplasma gondii). The research reveals that the nuclear basket consists of eight struts emanating from a double nuclear ring (NR), which terminate in a distal globular density. This density is thought to serve as a docking site for mRNA preprocessing before nucleocytoplasmic transport. The basket's architecture is stabilized by a hub of nucleoporins (Nups) in the nuclear ring, which bind to basket-forming Mlp/Tpr proteins. The coiled-coil domains of Mlp/Tpr form the struts, while their unstructured termini constitute the distal densities. The study also highlights the importance of the double NR in stabilizing the basket, as single NR variants do not support a stable basket. The basket's distal density contains the N/C termini of the strut-forming proteins, which serve as a docking platform for cargo and nuclear periphery elements. The research provides a detailed molecular architecture of the yeast and mammalian baskets, revealing their structural similarities and differences. The findings suggest that the basket's dynamic nature allows it to interact with various proteins and may have additional components beyond the identified ones. The study also discusses the functional implications of the basket's structure, including its role in chromatin organization and mRNA transport. The results highlight the importance of the NPC's structural plasticity and the need for further studies to understand the basket's role in different cellular contexts.