1. Rad54:
The Motor of
Homologous
Recombination

2. Rad54: DNA Translocation
The DNA translocation activity (forming positive and negative
supercoils) is required for all other Rad54 activities in the cell
Mazin et al. 2010

3. Rad54: Chromatin Remodeling
The chromatin remodeling and protein (histone) displacement activities
free the DNA for processing by other proteins (such as Rad51 and Rad52)
Mazin et al. 2010

4. Rad54: Rad51 Interaction
Rad54 stabilizes the Rad51 nucleoprotein filament and also stimulates
stand invasion
Mazin et al. 2010

5. Rad54: Dual Threat
Rad54 can both stabilize the Rad51 filament (in the presence of Ca2+)
and dissociate Rad51 (in the absence of Ca2+)
-Dissociation of Rad51 is a result of the translocation activity
Mazin et al. 2010

6. Rad54: Branch Migration
The branch migration activity allows for processing of HR intermediates
-Mus81 activation by Rad54 resolves HR intermediates
Mazin et al. 2010

7. The ATPase Motor
All Rad54 activities (with the exception of Rad51 stabilization)
require the ATPase activity
Walker A Box
[G,X,G,K,S/T]

8. The ATPase Motor Structure of the “Walker A Box”
-Site of ATP binding and hydrolysis
T184
Zebrafish Rad54
C-terminal domain
K183
L181
Thoma et al. 2005

9. Conserved YET Disputed
Sequence
PCNA Interacting Protein sequence Box (PIP Box) (Burgess et al) OR
-DNA binding sequence extending Motif III (Zhang et al)
-Both agree this sequence is necessary for ATPase activity

10. Conserved YET Disputed
Sequence
Tyrosine and Phenylalanine mutants have
shown significant decreases in activity
Thoma et al. 2005

11. Hydropathy Plot
No significant hydrophobic residues with some more significant
hydrophilic residues
-Consistent with a DNA-interacting protein

12. References