Cortical Num1p interacts with the dynein intermediate chain Pac11p and cytoplasmic microtubules in budding yeast.
Num1p, a cortical 313-kD protein, controls cytoplasmic microtubule (cMT) functions and nuclear migration through the bud neck in anaphase cells. A green fluorescent protein (GFP)-Num1p fusion protein localizes at the bud tip and the distal mother pole of living cells, apparently forming cMT capture sites at late anaphase. In addition, galactose-induced GFP-Num1p is seen at the bud neck and in lateral regions of the mother cortex. The bud tip location of Num1p depends on Bni1p but does not require Kar9p, Dyn1p, or cMTs, whereas cMT contacts with polar Num1p dots are reduced in cells lacking Dyn1p. Num1p associates with the dynein intermediate chain Pac11p in the presence of Dyn1p, and with the alpha-tubulin Tub3p, as shown by coimmune precipitation of tagged proteins. Num1p also forms a complex with Bni1p and Kar9p, although Num1p is not required for Bni1p- and Kar9p-dependent nuclear migration to the bud neck in preanaphase cells. Our data suggest that Num1p controls nuclear migration during late anaphase by forming dynein-interacting cortical cMT capture sites at both cellular poles. In addition, Num1p may transiently cooperate with an associated Bni1p-Kar9p complex at the bud tip of early anaphase cells.
Max-Planck Institute for Experimental Medicine, D-37075 Göttingen, Germany.
M
M
Farkasovsky
H
H
Küntzel
D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D002467:Cell Nucleus / Q000235:genetics / Q000502:physiology; D016764:Cell Polarity; D003593:Cytoplasm / Q000502:physiology; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000032:analysis; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin / Q000235:genetics / Q000502:physiology
D002135:Calcium-Binding Proteins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D008164:Luminescent Proteins; C071961:NUM1 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin; D049452:Green Fluorescent Proteins; D004398:Dyneins