SBT6.1 Antibody

Serine protease that catalyzes the first step (site-1 cleavage) in the proteolytic activation of various factors, prior to site-2 cleavage. Part of a regulated intramembrane proteolysis (RIP) cascade. Cleaves BZIP17 and BZIP28 after the Arg-Arg-Ile-Leu (RRIL) motif. May cleave BZIP49 after the RRIL motif. Targets the membrane-associated BZIP17 factor, which functions as a stress sensor and transducer in a signaling pathway that resembles an ER stress response. Following salt stress, BZIP17 is cleaved by SBT6.1 (S1P) and S2P at the C-terminus and the N-terminal bZIP component is translocated to the nucleus, where it activates the expression of salt stress response genes. Cleaves the pectinesterases PME1 after the Arg-Arg-Leu-Met (RRLM) and Arg-Arg-Leu-Leu (RRLL) motifs, and PME5 after the Arg-Arg-Leu-Leu (RRLL) and Arg-Lys-Leu-Met (RKLM) motifs. This processing and C-terminus release occurs in the Golgi apparatus and is required for cell wall targeting of pectinesterases. Thus, SBT6.1 mediates the regulated release of mature pectinesterases from the Golgi. Cleaves the peptide growth factor RALF23 after the Arg-Arg-Ile-Leu (RRIL) motif. This processing is required for RALF23 function in the negative regulation of brassinolide (BL)-mediated signaling pathway (e.g. BL-induced hypocotyl elongation and branching limitation).