MMS22L (Methyl methanesulfonate-sensitivity protein 22-like) is found in yeast, plants and vertebrates, and is integrally concerned with DNA forking and repair mechanisms during replication. MMS22L complexes with TONSL and this complex accumulates at regions of ssDNA associated with distressed replication forks or at processed DNA breaks. Its depletion results in high levels of endogenous DNA double-strand breaks caused by an inability to complete DNA synthesis after replication fork collapse [1]. Thus the complex mediates recovery from replication stress and homologous recombination in vertebrates, yeasts and plants [2,3]. This family is the more N-terminal region of the proteins.

1: The MMS22L-TONSL complex mediates recovery from replication stress and homologous recombination. O'Donnell L, Panier S, Wildenhain J, Tkach JM, Al-Hakim A, Landry MC, Escribano-Diaz C, Szilard RK, Young JT, Munro M, Canny MD, Kolas NK, Zhang W, Harding SM, Ylanko J, Mendez M, Mullin M, Sun T, Habermann B, Datti A, Bristow RG, Gingras AC, Tyers MD, Brown GW, Durocher D; Mol Cell. 2010;40:619-631. PMID:21055983

2: Identification of the MMS22L-TONSL complex that promotes homologous recombination. Duro E, Lundin C, Ask K, Sanchez-Pulido L, MacArtney TJ, Toth R, Ponting CP, Groth A, Helleday T, Rouse J; Mol Cell. 2010;40:632-644. PMID:21055984

3: A genome-wide camptothecin sensitivity screen identifies a mammalian MMS22L-NFKBIL2 complex required for genomic stability. O'Connell BC, Adamson B, Lydeard JR, Sowa ME, Ciccia A, Bredemeyer AL, Schlabach M, Gygi SP, Elledge SJ, Harper JW; Mol Cell. 2010;40:645-657. PMID:21055985