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  • Mitotic HOOK3 phosphorylation by ERK1c drives microtubule-dependent Golgi destabilization and fragmentation.

Mitotic HOOK3 phosphorylation by ERK1c drives microtubule-dependent Golgi destabilization and fragmentation.

iScience (2021-07-01)
Inbal Wortzel, Galia Maik-Rachline, Suresh Singh Yadav, Tamar Hanoch, Rony Seger
ABSTRACT

ERK1c is an alternatively spliced isoform of ERK1 that specifically regulates mitotic Golgi fragmentation, which allows division of the Golgi during mitosis. We have previously shown that ERK1c translocates to the Golgi during mitosis where it is activated by a resident MEK1b to induce Golgi fragmentation. However, the mechanism of ERK1c functions in the Golgi remained obscure. Here, we searched for ERK1c substrates and identified HOOK3 as a mediator of ERK1c-induced mitotic Golgi fragmentation, which requires a second phosphorylation by AuroraA for its function. In cycling cells, HOOK3 interacts with microtubules (MTs) and links them to the Golgi. Early in mitosis, HOOK3 is phosphorylated by ERK1c and later by AuroraA, resulting in HOOK3 detachment from the MTs, and elevated interaction with GM130. This detachment modulates Golgi stability and allows fragmentation of the Golgi. This study demonstrates a novel mechanism of Golgi apparatus destabilization early in mitosis to allow mitotic progression.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Monoclonal Anti-β-Tubulin antibody produced in mouse, clone TUB 2.1, ascites fluid
Roche
Anti-GFP, from mouse IgG1κ (clones 7.1 and 13.1)
Sigma-Aldrich
Duolink® In Situ Detection Reagents Red
Sigma-Aldrich
Anti-MAP Kinase (ERK-1, ERK-2) antibody produced in rabbit, whole antiserum