DNA mismatch repair protein MutS alpha complex (MutSα) (MutSα)

The MutS alpha (MutSα) complex is a critical heterodimeric protein assembly composed of MSH2 and MSH6 subunits, serving as a primary sensor in the eukaryotic DNA mismatch repair (MMR) pathway [1][2]. It specifically recognizes single-base mismatches and small insertion-deletion loops (IDLs) that escape DNA polymerase proofreading during replication [2][3]. Upon binding to a mismatch, the complex utilizes its ATPase activity to undergo a conformational change, facilitating the recruitment of the MutL alpha complex to initiate the excision and resynthesis of the erroneous DNA strand [1][4]. Beyond repair, MutSα plays a pivotal role in signaling apoptosis in response to certain types of DNA damage, such as those induced by alkylating agents like temozolomide [5]. Mutations in the genes encoding MSH2 or MSH6 are a hallmark of Lynch syndrome, leading to microsatellite instability (MSI) and a significantly increased risk of colorectal, endometrial, and other cancers [6]. In oncology, the status of the MutSα complex is a vital biomarker; its deficiency renders tumors resistant to some conventional chemotherapies but highly sensitive to immune checkpoint inhibitors [7]. Furthermore, recent therapeutic developments have identified synthetic lethal targets, such as WRN helicase, which can be inhibited to selectively kill cells lacking functional MutSα [8].

Other names

MSH2-MSH6 complexMutS alphaMutS-alphaMutS-alpha complexMismatch repair complex 1

Recognition of DNA mismatches and DNA adducts to initiate repair or apoptosis; synthetic lethal interaction with WRN helicase inhibitors in deficient states.