Telophase disc: a new mammalian mitotic organelle that bisects telophase cells with a possible function in cytokinesis

Abstract

We have discovered a novel mitosis-specific human autoantigen that arises at the centromeres of prophase chromosomes, but ultimately participates in formation of an organelle that bisects the cell at late anaphase and during telophase. The organelle, discernible as a three-dimensional disc by confocal microscopy, encompasses the entire midzone diameter, and its distribution survives disassembly of interpolar microtubules by cold temperature treatment and detergent lysis of cells. Cytokinetic furrow contraction proceeds normally in dihydrocytochalasin B (DCB)-treated cells, and antigen distribution in the furrow is unaltered. In DCB, the furrow retracts in early interphase, coincident with loss of normal membrane association with the disc, resulting in the formation of binucleate cells. The midzone disc in both drug-treated and normal cells is present at the correct time and position to play a central role in cytokinesis. By immunocytochemistry, the disc appears to contain myosin but not actin. The position of the disc and the possible presence of myosin suggest that cytokinesis may involve the interaction of the disc organelle with actin in the cell cortex to produce cleavage in mammalian cells.

NudCL2 is essential for cytokinesis by stabilizing RCC2 with Hsp90 at the midbody

“…We and other groups found that RCC2 localized at the midbody during cytokinesis (Fig. 3p-r) 35 . However, whether RCC2 plays a role in cytokinesis is largely unknown.…”

“…RCC2, also known as telophase disc protein of 60 kDa (TD-60), was reported to take part in spindle assembly and cell migration [35][36][37][38][39] . We and other groups found that RCC2 localized at the midbody during cytokinesis (Fig.…”

“…Thus, our data provide a previously undescribed function of NudCL2 in cytokinesis. RCC2, a member of regulator of chromatin condensation 1 (RCC1) superfamily, is initially identified as a telophase disk-binding protein during mitosis and acts as a specific guanine exchange factor (GEF) for small G proteins, Rac1 and RalA [35][36][37][38] .…”

“…RCC2 also is considered as a member of the chromosomal passenger complex (CPC) and dynamically ties to the inner centromeres during prophase. It binds to the midzone of the mitotic spindle during anaphase, and then accumulates at the midbody during cytokinesis 35,36 . RCC2 is required for prometaphase to metaphase progression by regulating proper kinetochore-microtubule attachments 37,38 .…”

A pan‑cancer analysis of RCC2 and its interaction with HMGA2 protein in an in vitro model of colorectal cancer cells

“…Regulator of chromosome condensation 2 (RCC2), also known as telophase disc-60 (TD60), was initially identified in the anaphase spindle midzone (1). RCC2 is an essential protein in the chromosomal passenger complex (2).…”