Proprotein convertases are required for KISS1 processing.

<p>A. Amino acid sequence of KISS1 showing three predicted PC cleavage sites − RK, RR and KR in bold. Note: DYKDDDDK at position 68 is the FLAG epitope tag used for several of the studies described in this manuscript. B. Treatment of C8161.9, MelJuSo, HeLa, COS7 and HEK293 cells over-expressing KISS1 with the general PC inhibitor Dec-RVKR-CMK (100 µM) blocked KISS1 processing as detected by immunoprecipitation and immunoblot using anti-KISS1 antibody [See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084958#pone-0084958-g001" target="_blank">Figure 1</a> and Materials and Methods for details]. C. Over-expression of KISS1 and the biological PC inhibitor V5-tagged α1-PDX also resulted in loss of KISS1 processing into KP. Polypeptide sizes correspond to those shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084958#pone-0084958-g001" target="_blank">Figure 1</a>.