AKAP95 interacts with nucleoporin TPR in mitosis and is important for the spindle assembly checkpoint

Cell Cycle. 2017 May 19;16(10):947-956. doi: 10.1080/15384101.2017.1310350. Epub 2017 Apr 5.

Abstract

Faithful chromosome segregation during mitosis relies on a proofreading mechanism that monitors proper kinetochore-microtubule attachments. The spindle assembly checkpoint (SAC) is based on the concerted action of numerous components that maintain a repressive signal inhibiting transition into anaphase until all chromosomes are attached. Here we show that A-Kinase Anchoring Protein 95 (AKAP95) is necessary for proper SAC function. AKAP95-depleted HeLa cells show micronuclei formed from lagging chromosomes at mitosis. Using a BioID proximity-based proteomic screen, we identify the nuclear pore complex protein TPR as a novel AKAP95 binding partner. We show interaction between AKAP95 and TPR in mitosis, and an AKAP95-dependent enrichment of TPR in the spindle microtubule area in metaphase, then later in the spindle midzone area. AKAP95-depleted cells display faster prometaphase to anaphase transition, escape from nocodazole-induced mitotic arrest and show a partial delocalization from kinetochores of the SAC component MAD1. Our results demonstrate an involvement of AKAP95 in proper SAC function likely through its interaction with TPR.

Keywords: mitotic arrest deficient; translocated in promoter region.

MeSH terms

  • A Kinase Anchor Proteins / genetics*
  • Chromosome Segregation / genetics
  • HeLa Cells
  • Humans
  • M Phase Cell Cycle Checkpoints / genetics*
  • Mitosis / genetics
  • Nuclear Pore / genetics
  • Nuclear Pore / metabolism
  • Nuclear Pore Complex Proteins / genetics*
  • Nuclear Pore Complex Proteins / metabolism
  • Protein Binding
  • Proteomics*
  • Proto-Oncogene Proteins / genetics*
  • Spindle Apparatus / genetics
  • Spindle Apparatus / metabolism

Substances

  • A Kinase Anchor Proteins
  • AKAP8 protein, human
  • Nuclear Pore Complex Proteins
  • Proto-Oncogene Proteins
  • TPR protein, human