Phosphorylation regulates targeting of cytoplasmic dynein to kinetochores during mitosis

Abstract

Cytoplasmic dynein functions at several sites during mitosis; however, the basis of targeting to each site remains unclear. Tandem mass spectrometry analysis of mitotic dynein revealed a phosphorylation site in the dynein intermediate chains (ICs) that mediates binding to kinetochores. IC phosphorylation directs binding to zw10 rather than dynactin, and this interaction is needed for kinetochore dynein localization. Phosphodynein associates with kinetochores from nuclear envelope breakdown to metaphase, but bioriented microtubule (MT) attachment and chromosome alignment induce IC dephosphorylation. IC dephosphorylation stimulates binding to dynactin and poleward streaming. MT depolymerization, release of kinetochore tension, and a PP1-γ mutant each inhibited IC dephosphorylation, leading to the retention of phosphodynein at kinetochores and reduced poleward streaming. The depletion of kinetochore dynactin by moderate levels of p50(dynamitin) expression disrupted the ability of dynein to remove checkpoint proteins by streaming at metaphase but not other aspects of kinetochore dynein activity. Together, these results suggest a new model for localization of kinetochore dynein and the contribution of kinetochore dynactin.

Spindly switch controls anaphase: Spindly and RZZ functions in chromosome attachment and mitotic checkpoint control

“…Phospho-dynein interacts preferentially with ZW10 and is found to be associated with kinetochores from prometaphase until bi-orientation, upon which dynein becomes dephosphorylated, able to interact with dynactin and translocates to the poles. 30 In addition, this switch might depend on a change in the kintochore binding affinity of the RZZ complex, which might be regulated by Spindly as discussed below.…”

“…In prometaphase, dynein is strongly localized to the fibrillar corona until microtubule attachment is established upon which dynein translocates from the kinetochore to the spindle pole. [27][28][29][30] The localization of the dynein motor to this fibrous corona is very dynamic and depends on the RZZ complex, 16,31 and the recently discovered protein Spindly.…”

Dynein prevents erroneous kinetochore-microtubule attachments in mitosis

“…10 The Rod, ZW10 and Zwilch (RZZ) complex and Spindly target Keywords: Aurora A, Dynein, error correction, kinetochore, spindle pole Dynein specifically to kinetochores, coupling its function to kinetochore-microtubule attachments and the spindle assembly checkpoint. 11 Thus, a number of different binding partners, together with a diverse distribution of specific subunits 12 and their phospho-regulation, 13 allow a single motor protein -Dyneinto be involved in numerous independent cellular functions, including chromosome congression. [14][15][16] Another kinetochore-localized motor protein involved in chromosome movements is the kinesin-7 CENP-E.…”

A dynein independent role of Tctex-1 at the kinetochore

“…6A and B). Furthermore, knocking down of ZW10, a component of the RZZ (Rod/ZW10/ Zwilch) complex that recruits dynein to kinetochores, 27,28 significantly reduced the level of dynein at unattached kinetochores ( Fig. 6A and C).…”