Student number__________ Grader number___________ Biol110-Cell Biology Fall 2010 Problem Key #4 Question #1:The Nucleoplasm and Nucleocytoplasmic Trafficking What are the two main functions of the nuclear pore complex (NPC) at the nuclear envelope? (4 pts) It serves as a size selective barrier that excludes particles greater than ~40 kDa (or ~4 nm). (2 pts). It serves as a carrier channel to facilitate the transport of large karyopherin-cargo complexes across. (2 pts) Structurally, what is the main function of the nucleoporins forming the NPC ring-scaffold? (2 pts) They maintain and shape the curved membrane of the nuclear pore and function as a stent that keeps the nuclear pore membrane from ‘collapsing’ on itself, or closing (i.e. it keeps the nuclear pore open). (2 pts) They also serve as an attachment site for the FG nucleoporins that form the gate (1 pt)What are the two main functions of the nucleoporins containing FG motifs? (4 pts) They interact to form a size selective gate that keeps large particles from diffusing across. (2 pts). They serve as specific docking sites for karyopherins to facilitate their movement along the
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