Abstract

TRAMM was originally identified as a protein that co-precipitates with the TRAPP (transport protein particle) complex that functions in membrane trafficking. Recent work in our laboratory suggested a role for this protein in mitosis, specifically in chromosome congression prior to metaphase. In the early stages of mitosis, TRAMM is post- translationally modified by phosphorylation. Knockdown of the protein causes it to affect the localization of various kinetochore proteins with the strongest effect on CENP-E. The two proteins were also shown to interact using a yeast two hybrid assay (Milev et al., 2015).

In this study, I show that TRAMM also interacts with CENP-E through a co- immunoprecipitaiton assay and this interaction appears to be enhanced in mitotic lysates. Using various inhibitors of mitotic kinases, I further show that only inhibition of Cdk1 prevents the phosphorylation of TRAMM. This suggests that Cdk1, apart from the other mitotic kinases, has a role in phosphorylating TRAMM. Furthermore, I also use bioinformatics tools to predict the structure of TRAMM. Finally I express and purify a recombinant form of TRAMM in a homogeneous monodispersed protein sample.