Human SHPRH is a ubiquitin ligase for Mms2-Ubc13-dependent polyubiquitylation of proliferating cell nuclear antigen

Proc Natl Acad Sci U S A. 2006 Nov 28;103(48):18107-12. doi: 10.1073/pnas.0608595103. Epub 2006 Nov 15.


Human SHPRH gene is located at the 6q24 chromosomal region, and loss of heterozygosity in this region is seen in a wide variety of cancers. SHPRH is a member of the SWI/SNF family of ATPases/helicases, and it possesses a C(3)HC(4) RING motif characteristic of ubiquitin ligase proteins. In both of these features, SHPRH resembles the yeast Rad5 protein, which, together with Mms2-Ubc13, promotes replication through DNA lesions via an error-free postreplicational repair pathway. Genetic evidence in yeast has indicated a role for Rad5 as a ubiquitin ligase in mediating the Mms2-Ubc13-dependent polyubiquitylation of proliferating cell nuclear antigen. Here we show that SHPRH is a functional homolog of Rad5. Similar to Rad5, SHPRH physically interacts with the Rad6-Rad18 and Mms2-Ubc13 complexes, and we show that SHPRH protein is a ubiquitin ligase indispensable for Mms2-Ubc13-dependent polyubiquitylation of proliferating cell nuclear antigen. Based on these observations, we predict a role for SHPRH in promoting error-free replication through DNA lesions. Such a role for SHPRH is consistent with the observation that this gene is mutated in a number of cancer cell lines, including those from melanomas and ovarian cancers, which raises the strong possibility that SHPRH function is an important deterrent to mutagenesis and carcinogenesis in humans.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Amino Acid Sequence
  • Cell Line
  • DNA / genetics
  • DNA Helicases / chemistry
  • DNA Helicases / genetics
  • DNA Helicases / isolation & purification
  • DNA Helicases / metabolism*
  • Humans
  • Molecular Sequence Data
  • Proliferating Cell Nuclear Antigen / genetics
  • Proliferating Cell Nuclear Antigen / metabolism*
  • Protein Binding
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins / chemistry
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Ubiquitin / metabolism*
  • Ubiquitin-Conjugating Enzymes / genetics
  • Ubiquitin-Conjugating Enzymes / metabolism*
  • Ubiquitin-Protein Ligases / chemistry
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / isolation & purification
  • Ubiquitin-Protein Ligases / metabolism*


  • Proliferating Cell Nuclear Antigen
  • Saccharomyces cerevisiae Proteins
  • Ubiquitin
  • DNA
  • Ubiquitin-Conjugating Enzymes
  • SHPRH protein, human
  • Ubiquitin-Protein Ligases
  • Adenosine Triphosphatases
  • RAD5 protein, S cerevisiae
  • DNA Helicases