Figure 6
Analyzing the role of SKA1 in MT dynamics. (a) DUF1395 domain sequence comparison showing highly conserved amino acids (red) across multiple organisms: CAB82670 (Arabidopsis thaliana), XP_478114 (Oryza sativa), CAA21578 (Caenorhabditis elegans), CAE58950 (Caenorhabditis briggsae), AAH15705 (Homo sapiens), XP_512132 (Pan troglodytes), XP_548812 (Canis familiaris), XP_584361 (Bos Taurus), BAB28731 (Mus musculus), NP_079857 (Mus musculus), XP_214527 (Rattus norvegicus), AAH76006 (Danio rerio), and XP_553928 (Anopheles gambiae str). (b) Time-lapse microscopy monitoring spindle assembly in U2OS cells for 2,100 seconds. Scale bar: 3 μm. Panels c to f show green fluorescent protein (GFP)-SKA1 localization in (c) metaphase, (d) anaphase, and (e,f) interphase. (f) Localization of GFP-SKA1 in interphase cells over-expressing GFP-SKA1 for more than 24 hours. Scale bar: 5 μm. Panels g and h show GFP-SKA1 localization in transfected HeLa cell (g) before and (h) 30 minutes after 10 μmol/l nocodozole treatment; (i,j) negative control images. Scale bar: 5 μm. (k) Model for SKA1's role in maintaining spindle integrity. SKA1 bundles microtubules (MT) and generates thicker and stronger fibers. Therefore, it prevents the loss of the spindle integrity before onsent of anaphase. Loss of this activity results in aberrant spindles with more than two poles.