[Protein SLFN14]: Shows no ribosome-associated and endoribonuclease activities. ; [C-terminally truncated SLFN14 endoribonuclease]: Displays polysome-associated endoribonuclease activity towards mRNAs and rRNAs (PubMed:25996083). May play a role in RNA surveillance pathways by recognizing stalled ribosomes and triggering endonucleolytic cleavage of aberrant mRNAs (Probable). Cleaves different types of rRNAs and mRNAs in a magnesium- and manganese-dependent and ATP-independent manner (By similarity). Involved in correct maturation of megakaryocytes and especially important for proplatelet extension.