TRAF3 is a critical regulator of plasma cell homeostasis. TRAF3 is an adaptor that recruits a TRAF2, cIAP1, and cIAP2 E3 ubiquitin ligase complex to NIK, leading to rapid turnover in resting B cells. Low levels of TRAF3 lead to NIK stabilization, activation of the alternative NF-kB pathway, and plasma cell survival. High levels of TRAF3 in transgenic B cells results in reduced B-cell numbers, but plasmacytosis by an unresolved mechanism, perhaps related to increased plasma cell differentiation.