MMS1 is a protein that protects against replication-dependent DNA damage in Saccharomyces cerevisiae [1]. MMS1 belongs to the DDB1 family of cullin 4 adaptors and the two proteins are homologous. MMS1 bridges the interaction of MMS22 and Crt10 with Cul8/Rtt101 [2]. Cul8/Rtt101 is a cullin protein involved in the regulation of DNA replication subsequent to DNA damage. The N-terminal region of MMS1 and the C-terminal of MMS22 are required for the the MMS1-MMS22 interaction [3]. The human HIV-1 virion-associated protein Vpr assembles with DDB1 through interaction with DCAF1 (chromatin assembly factor) to form an E3 ubiquitin ligase that targets cellular substrates for proteasome-mediated degradation and subsequent G2 arrest [4].

1: MMS1 protects against replication-dependent DNA damage in Saccharomyces cerevisiae. Hryciw T, Tang M, Fontanie T, Xiao W; Mol Genet Genomics. 2002;266:848-857. PMID:11810260

2: Rtt101 and Mms1 in budding yeast form a CUL4(DDB1)-like ubiquitin ligase that promotes replication through damaged DNA. Zaidi IW, Rabut G, Poveda A, Scheel H, Malmstrom J, Ulrich H, Hofmann K, Pasero P, Peter M, Luke B; EMBO Rep. 2008;9:1034-1040. PMID:18704118

3: Cul8/Rtt101 forms a variety of protein complexes that regulate DNA damage response and transcriptional silencing. Mimura S, Yamaguchi T, Ishii S, Noro E, Katsura T, Obuse C, Kamura T; J Biol Chem. 2010; [Epub ahead of print] PMID:20139071

4: DDB1 and Cul4A are required for human immunodeficiency virus type 1 Vpr-induced G2 arrest. Tan L, Ehrlich E, Yu XF; J Virol. 2007;81:10822-10830. PMID:17626091