Mechanistic insights into proteolytic activation ofmembrane-bound NAC transcription factor SlNACMTF3 intomato plants under heat stress

Heat stress activates the tomato membrane-bound transcription factor SlNACMTF3 by rhomboid protease SlRP3 cleavage at an ISK motif near its transmembrane domain.

• Why it matters: Stress perception at the plasma membrane requires a molecular mechanism linking membrane activation to rapid transcriptional cascades, which was unknown for SlNACMTF3.
• What they did: SlRP3 recognizes an ISK motif for cleavage and releases SlNACMTF3; SlRP3 and SlNACMTF3 co-localize in the same plasma membrane microdomain and interact directly, supported by molecular dynamics.
• The result: SlRP3 residue mutations and SlRP3 transient knockdown impair SlNACMTF3 activation, reduce stress-responsive gene expression, and coordinately affect cellular ROS detoxification in tomato plants.