Essential for synapsis surveillance during meiotic prophase via the recruitment of ATR activity. Plays a key role in the male mid-pachytene checkpoint and the female meiotic prophase checkpoint: required for efficient build-up of ATR activity on unsynapsed chromosome regions, a process believed to form the basis of meiotic silencing of unsynapsed chromatin (MSUC) and meiotic prophase quality control in both sexes. Required for the DNA double-strand break-independent, BRCA1-dependent activation of ATR on the sex chromosomes that is essential for normal sex body formation (By similarity). Interacts with HORMAD1. Preferentially localizes to unsynapsed or desynapsed chromosomal regions during the male and female prophase I stage of meiosis. TRIP13 is required for depletion from synapsed chromosomes (By similarity). Phosphorylated in a SPO11-dependent manner.