Before revision: Measurement of the life time of attachments formed by a single microtubule (MT) with a single kinetochore (kt) {\it in-vitro} under force-clamp conditions  revealed a catch-bond-like behavior.
After revision: Measurement of the life time of attachments formed by a single microtubule (MT) with a single kinetochore (kt) {\it in-vitro} under force-clamp conditions had earlier revealed a catch-bond-like behavior.