title: S. pombe Pbh1p: an inhibitor of apoptosis domain containing protein is essential for chromosome segregation.
abstract: Proteins containing the baculovirus inhibitor of apoptosis repeats (BIR domains) have been identified in a wide range of species. BIR domain containing proteins are thought to inhibit caspases and thereby cause inhibition of apoptosis. A BIR domain containing protein has been recently identified by the Schizosaccharomyces pombe genome sequencing project. However, caspase-like proteins have not been found in yeasts, suggesting that the BIR domain containing proteins might play a fundamental role in cell regulation, in addition to their well-characterized role in inhibition of apoptosis. In this study, we have characterized Pbh1p, an S. pombe BIR domain containing protein. Construction and analysis of a null mutant in pbh1+ revealed that pbh1+ is essential for cell viability. Moreover, cells devoid of Pbh1p are defective in chromosome condensation and chromosome segregation. Thus, proper chromosome segregation requires the function of Pbh1p. Over-production of Pbh1p led to abnormalities in mitosis and cytokinesis, suggesting that the levels of Pbh1p are important for regulation of mitosis and cytokinesis.
authors.affiliation: Institute of Molecular Agrobiology, The National University of Singapore, Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Rajagopalan
authors.forename: M K
authors.initials: MK
authors.lastname: Balasubramanian
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics*; D020090:Chromosome Segregation / Q000235:genetics*; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D051034:Inhibitor of Apoptosis Proteins; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012568:Schizosaccharomyces / Q000737:chemistry / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D016415:Sequence Alignment; D000077022:Survivin; D014764:Viral Proteins / Q000235:genetics
chemical_list: C400706:Bir1 protein, S pombe; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D051034:Inhibitor of Apoptosis Proteins; D029702:Schizosaccharomyces pombe Proteins; D000077022:Survivin; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus