SKP2 and breast carcinoma: More recently, it was demonstrated that Skp2 facilitates the activation of Akt through ubiquitination downstream of ErbB receptor signaling in Her2-positive breast cancer [4], and that Skp2, by triggering NSB1 ubiquitination, represents a key component for the Mre11/Rad50/NBS1 complex-mediated activation of ATM in response to DNA double-strand breaks [5].