(e,f) MBd enrichment in cancer cells leads to increased anchorage-independent growth. MKLP1-GFP-expressing HeLa cells are separated into 'MBd-high' and 'MBd-low' subpopulations. An increase in the 'MBd high' over 'MBd low' ratio is associated with an increase in soft-agar colony formation (e). No significant difference was observed when the enrichment of the MBd-high subpopulation was less than threefold. More soft-agar colonies are formed when MBds are enriched by NBR1 depletion (NBR1 shRNA) in HeLa (f, left; P=0.0012, n=3) and mouse 134-4 cells (f, right; P=0.0086, n=3); control, shNT. Data are mean±s.d., and the colony number (e,f) is the sum of INT-violet-stained colonies from ten random fields. 