Human enhancer of invasion-cluster, a coiled-coil protein required for passage through mitosis.
In a cross-species overexpression approach, we used the pseudohyphal transition of Saccharomyces cerevisiae as a model screening system to identify human genes that regulate cell morphology and the cell cycle. Human enhancer of invasion-cluster (HEI-C), encoding a novel evolutionarily conserved coiled-coil protein, was isolated in a screen for human genes that induce agar invasion in S. cerevisiae. In human cells, HEI-C is primarily localized to the spindle during mitosis. Depletion of HEI-C in vivo with short interfering RNAs results in severe mitotic defects. Analysis by immunofluorescence, flow cytometry analysis, and videomicroscopy indicates that HEI-C-depleted cells form metaphase plates with normal timing after G(2)/M transition, although in many cases cells have disorganized mitotic spindles. Subsequently, severe defects occur at the metaphase-anaphase transition, characterized by a significant delay at this stage or, more commonly, cellular disintegration accompanied by the display of classic biochemical markers of apoptosis. These mitotic defects occur in spite of the fact that HEI-C-depleted cells retain functional cell cycle checkpoints, as these cells arrest normally following nocodazole or hydroxyurea treatment. These results place HEI-C as a novel regulator of spindle function and integrity during the metaphase-anaphase transition.
Einarson
Margret B
MB
Division of Basic Science, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
Cukierman
Edna
E
Compton
Duane A
DA
Golemis
Erica A
EA
D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D048429:Cell Size; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000378:metabolism; D011487:Protein Conformation; D034741:RNA, Small Interfering / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D008941:Spindle Apparatus / Q000378:metabolism
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; C486648:HAUS1 protein, human; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; D015739:Nocodazole