A mutation in a gene encoding a specific nuclear pore complex protein could lead to which of the following cellular dysfunctions?
Correct: C
The nuclear pore complex (NPC) is responsible for regulating the bidirectional transport of macromolecules between the nucleus and the cytoplasm. Ribosomal proteins are synthesized in the cytoplasm, imported into the nucleus through the NPC, and then assembled with rRNA (synthesized in the nucleolus) to form ribosomal subunits, which are subsequently exported back to the cytoplasm. A defective NPC protein would therefore impair the import of ribosomal proteins into the nucleus, hindering ribosome assembly. Phospholipid synthesis occurs in the ER, lysosomal enzyme sorting in the Golgi, and mitochondrial DNA is transcribed within mitochondria, none of which directly depend on the nuclear pore complex for their primary function.