A large-scale sORF screen identifies putative microproteins involved in cancer cell fitness.

The human genome contains thousands of potentially coding short open reading frames (sORFs). While a growing set of microproteins translated from these sORFs have been demonstrated to mediate important cellular functions, the majority remains uncharacterized. In our study, we performed a high-throughput CRISPR-Cas9 knock-out screen targeting 11,776 sORFs to identify microproteins essential for cancer cell line growth.

The N-terminal SAM domain of the dNTPase SAMHD1 is not required for inhibition by small molecule TH6342.

Sterile alpha motif and histidine-aspartic acid domain containing protein-1 (SAMHD1) is a deoxynucleoside triphosphate (dNTP) hydrolase that controls dNTP pools and detoxifies cancer cells of chemotherapy metabolites. TH6342 is a recently reported small molecule inhibitor of SAMHD1 that interacts with the protein and non-competitively prevents dimerisation, a prerequisite for catalysis. The binding site of TH6342 on SAMHD1 is currently unknown.

Identification and evaluation of small-molecule inhibitors against the dNTPase SAMHD1 via a comprehensive screening funnel.

SAMHD1 is a dNTP triphosphohydrolase governing nucleotide pool homeostasis and can detoxify chemotherapy metabolites controlling their clinical responses. To understand SAMHD1 biology and investigate the potential of targeting SAMHD1 as neoadjuvant to current chemotherapies, we set out to discover selective small-molecule inhibitors. Here, we report a discovery pipeline encompassing a biochemical screening campaign and a set of complementary biochemical, biophysical, and cell-based readouts for rigorous characterization of the screen output.