Functions as a component of the spindle pole body (SPB) half-bridge (PubMed:10684247, PubMed:11156974, PubMed:12486115, PubMed:14504268, PubMed:8070654). At the SPB, it is recruited by KAR1 and MPS3 to the SPB half-bridge and involved in the initial steps of SPB duplication (PubMed:11156974, PubMed:12486115, PubMed:14504268, PubMed:8070654). Also involved in connection with the protein kinase KIC1 in the maintenance of cell morphology and integrity (PubMed:9813095). May play a role in vesicle-mediated transport, in a VPS13-dependent manner (PubMed:28122955). Component of the spindle pole body (SPB), acting as the connector of microtubule arrays in the cytoplasm and the nucleoplasm, is involved in nuclear positioning before chromosome segregation, SPB separation, spindle formation, chromosome segregation, nuclear migration into the bud, nuclear reorientation after cytokinesis and nuclear fusion during conjugation. The SPB half-bridge, which is tightly associated with the cytoplasmic side of the nuclear envelope and the SPB, is playing a key role as the starting structure for and in the initiation of SPB duplication in G1. At the SPB half-bridge CDC31 interacts with KAR1, MPS3 and SFI1 (PubMed:12486115, PubMed:14504268). Interacts with KIC1 (PubMed:9813095). Interacts with VPS13 (PubMed:28122955). Associates with nuclear pore complexes (NPCs) (PubMed:10684247). Spindle pole body, SPB half- bridge (PubMed:8188750). Interacts with the nuclear pore complex (NPCs) at the nucleus envelope (PubMed:10684247). Belongs to the centrin family.