# Mitotic Kinases Aurora-A, Plk1, and Cdk1 Interact with Elk-1 Transcription Factor through the N-Terminal Domain

## TL;DR

This study shows that the Elk-1 transcription factor interacts with several mitotic kinases and identifies the region responsible for these interactions.

## Contribution

The first identification of Elk-1 interactions with Aurora-B, Plk1, and Cdk1, along with defining the N-terminal interaction domain.

## Key findings

- Elk-1 interacts with mitotic kinases Aurora-A, Aurora-B, Plk1, and Cdk1 via its N-terminal 205 amino acids.
- Elk-1 peptides containing putative phosphorylation sites are phosphorylated by these mitotic kinases in vitro.
- Bioinformatic analysis links Elk-1 to Plk and Aurora phosphoproteomes, suggesting new interaction partners.

## Abstract

Elk-1 is a member of the ETS domain transcription factor superfamily that is phosphorylated upon mitogen-activated protein kinase (MAPK) pathway activation, which in turn regulated its interaction with partner protein serum response factor (SRF), leading to formation of a ternary complex with DNA. It has previously been reported that Elk-1 interacts with a mitotic kinase Aurora-A, although the mechanisms or the relevance of this interaction was unclear. Elk-1 was also reported to be phosphorylated by CDK5 on Thr417 residue. In this study, we show for the first time that this transcription factor interacts not only with Aurora-A but also with other mitotic kinases Aurora-B, Plk1, and Cdk1, and we define the interaction domain on Elk-1 to the first N-terminal 205 amino acids. We also describe putative phosphorylation sites of these mitotic kinases on Elk-1 and show that Elk-1 peptides containing these residues get phosphorylated by the mitotic kinases in in vitro kinase assays. We also perform bioinformatic analysis of mitotic phosphoproteomes and determine potential interaction partners for Elk-1 in Plk or Aurora phosphoproteomes. We propose that understanding the dynamic phosphorylation of Elk-1 by mitotic kinases is important and that it can present a novel target for anticancer strategies.