Probable component of a transcriptional corepressor complex that acts downstream of MAX2 to negatively regulate karrikins/strigolactone responses (PubMed:23893171, PubMed:26546447). Probable target of MAX2 during germination and seedling photomorphogenesis (PubMed:26546447). Acts probably specifically in the karrikin pathway (PubMed:26754282). Interacts probably with TPL/TPR in an EAR-motif dependent manner. Interacts with TPL, TPR1, TPR2 and TPR4. Highly expressed in dry seeds. Expressed in seedlings, rosette leaves and senescing leaves. Detected in roots and axillary shoots (PubMed:23893171). Expressed in the primary rosette buds and expanding leaves of adult rosettes, the vasculature of the hypocotyls, cotyledons, and mature roots, in the midvein and petioles of young leaves, the young leaf periphery, stomata, and the root caps (PubMed:26546447). Peak of expression in seeds during maturation. Up-regulated by karrikins treatments (PubMed:20351290). Under MAX2-dependent negative feedback regulation (PubMed:23893171). Contains 1 EAR motif required for the interaction with TPR2. Low seed dormancy and short hypocotyls (PubMed:23893171). Suppresses max2 phenotypes associated with karrikin-KAI2-regulated growth (PubMed:26546447). Smax1 and smxl2 double mutants have substential reduction in hypocotyl elongation (PubMed:26754282). Belongs to the ClpA/ClpB family.