Component of SCF(SKP2A) E3 ubiquitin ligase complexes, which mediate the ubiquitination and subsequent proteasomal degradation of target proteins (including cell cycle repressors). Acts as an auxin receptor; one active auxin is indole-3-acetate. Regulates the stability of the transcription factors E2FC and DPB, repressors of cell proliferation. Confers increase tolerance to osmotic stress by promoting cell division, especially in meristems. Promotes the formation of lateral root primordia. Protein modification; protein ubiquitination. Part of a SCF (ASK-cullin-F-box) protein ligase complex. Interacts with CUL1 (RUB1-modified and non-modified isoforms), SKP1A, SKP1B and ASK18. Recruit DPB and phosphorylated E2FC. Interacts with auxin. Auxin controls the interaction with DPB. Expressed in embryo, seedlings, hypocotyl, roots, leaves and flowers. Widely expressed during the first stages of germination. In seedling, more intense in dividing areas, such as meristems and young organs. In leaves, confined to vascular tissue and stomatal cells. In roots, detected in tips, vascular cylinder of the distal part, and in lateral roots emerging primordia. Low levels in specific cells of root meristems. Cell-cycle regulated expression with higher levels during early S-phase and G2/M stages. Repressed by auxin through a ubiquitin-dependent pathway (at protein level). Only biologically active auxin promotes proteolysis of SKP2A. The F-box is necessary for the interaction with ASK proteins. Polyubiquitinated and subsequently targeted to proteasome. Auxin promotes this ubiquitination-mediated degradation.