Distinct but overlapping domains of AKAP95 are implicated in chromosome condensation and condensin targeting.
A-kinase (or PKA)-anchoring protein AKAP95 is a zinc-finger protein implicated in mitotic chromosome condensation by acting as a targeting molecule for the condensin complex. We have identified determinants of chromatin-binding, condensin-targeting and chromosome-condensation activities of AKAP95. Binding of AKAP95 to chromatin is conferred by residues 387-450 and requires zinc finger ZF1. Residues 525-569 are essential for condensation of AKAP95-free chromatin and condensin recruitment to chromosomes. Mutation of either zinc finger of AKAP95 abolishes condensation. However, ZF1 is dispensable for condensin targeting, whereas the C-terminal ZF2 is required. AKAP95 interacts with Xenopus XCAP-H condensin subunit in vitro and in vivo but not with the human hCAP-D2 subunit. The data illustrate the involvement of overlapping, but distinct, domains of AKAP95 for condensin recruitment and chromosome condensation and argue for a key role of ZF1 in chromosome condensation and ZF2 in condensin targeting. Moreover, condensin recruitment to chromatin is not sufficient to promote condensation.
Eide
Turid
T
Institute of Medical Biochemistry, University of Oslo, PO Box 1112, Blindern, N-0317 Oslo, Norway.
Carlson
Cathrine
C
Taskén
Kristin A
KA
Hirano
Tatsuya
T
Taskén
Kjetil
K
Collas
Philippe
P
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002875:Chromosomes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein; D017384:Sequence Deletion; D014981:Xenopus
C490117:AKAP8L protein, human; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D011994:Recombinant Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases