hMSH4-hMSH5 adenosine nucleotide processing and interactions with homologous recombination machinery.
We have previously demonstrated that the human heterodimeric meiosis-specific MutS homologs, hMSH4-hMSH5, bind uniquely to a Holliday Junction and its developmental progenitor (Snowden, T., Acharya, S., Butz, C., Berardini, M., and Fishel, R. (2004) Mol. Cell 15, 437-451). ATP binding by hMSH4-hMSH5 resulted in the formation of a sliding clamp that dissociated from the Holliday Junction crossover region embracing two duplex DNA arms. The loading of multiple hMSH4-hMSH5 sliding clamps was anticipated to stabilize the interaction between parental chromosomes during meiosis double-stranded break repair. Here we have identified the interaction region between the individual subunits of hMSH4-hMSH5 that are likely involved in clamp formation and show that each subunit of the heterodimer binds ATP. We have determined that ADP-->ATP exchange is uniquely provoked by Holliday Junction recognition. Moreover, the hydrolysis of ATP by hMSH4-hMSH5 appears to occur after the complex transits the open ends of model Holliday Junction oligonucleotides. Finally, we have identified several components of the double-stranded break repair machinery that strongly interact with hMSH4-hMSH5. These results further underline the function(s) and interactors of hMSH4-hMSH5 that ensure accurate chromosomal repair and segregation during meiosis.
Snowden
Timothy
T
Genetics and Molecular Biology Program, Kimmel Cancer Center, Philadelphia, Pennsylvania 19107.
Shim
Kang-Sup
KS
Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University School of Medicine and Public Health, Columbus, Ohio 43210.
Schmutte
Christoph
C
Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University School of Medicine and Public Health, Columbus, Ohio 43210.
Acharya
Samir
S
Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University School of Medicine and Public Health, Columbus, Ohio 43210.
Fishel
Richard
R
Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University School of Medicine and Public Health, Columbus, Ohio 43210. Electronic address: rfishel@osu.edu.
D000241:Adenosine / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045566:DNA, Cruciform / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008540:Meiosis / Q000235:genetics; D008954:Models, Biological; D008957:Models, Genetic; D011485:Protein Binding; D011995:Recombination, Genetic
D018797:Cell Cycle Proteins; D045566:DNA, Cruciform; C409221:MSH4 protein, human; C118481:MSH5 protein, human; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine