High impact information on ran

• Here, we report the three-dimensional structure of a complex between Ran bound to the nonhydrolyzable GTP analog GppNHp and a 462-residue fragment from Importin beta [1].
• Biochemically, RCC1 is a guanine-nucleotide-exchange factor for the nuclear Ras homologue Ran; it increases the dissociation of Ran-bound GDP by 10(5)-fold [2].
• The key distorter locus, Sd, is a dominant neomorphic allele encoding a truncated, but enzymatically active, RanGAP (RanGTPase-activating protein) whose nuclear mislocalization underlies distortion by disrupting the Ran signaling pathway [3].
• Distortion can be suppressed by overexpression of Ran or Ran guanine nucleotide exchange factor (RanGEF) in the male germ line, indicating that the primary consequence of nuclear mislocalization of RanGAP is reduction of intranuclear RanGTP levels [3].
• However, the extent of the role of the Ran pathway in mitosis in vivo is unclear [4].

Biological context of ran

• Crosstalk between the actin cytoskeleton and Ran-mediated nuclear transport [5].
• We find that, during mitosis, RCC1, the nucleotide exchange factor for Ran, is associated with chromatin, while Ran and RanL43E, an allele locked in the GTP-bound state, localize around the spindle [6].
• In addition, the Ran pathway is required for postmetaphase events, including chromosome segregation and the assembly of the microtubule midbody [4].

Anatomical context of ran

• The GTPase Ran regulates multiple cellular functions throughout the cell cycle, including nucleocytoplasmic transport, nuclear membrane assembly, and spindle assembly [6].

Other interactions of ran

• We conclude that mislocalization of Sd-RanGAP causes distortion by reducing nuclear RanGTP, thereby disrupting the Ran signaling pathway [7].
• Structural view of the Ran-Importin beta interaction at 2.3 A resolution [1].

References