MS-KIF18A, a kinesin is associated with estrogen receptor

The study of MS-KIF18A kinesin protein is focused on its cellular distribution and association with a cargo protein. Indirect immunofluorescence (IF) analyzed the intracellular distribution of endogenous MS-KIF18A and the transfected enhanced green fluorescence protein (eGFP)-MS-KIF18A in osteogenic cells. In both cases, the proteins were localized at the plasma membrane, cytosol, and nucleus. Bioinformatics analysis suggested interactions between MS-KIF18A and estrogen receptor (ERα) which were further elucidated by immunoprecipitation (IP). We identified interaction between endogenous MS-KIF18A with 66 and 46 kDa isoforms of ERα in MBA-15 cells. Moreover, MS-KIF18A and 66 kDa ERα complex has been demonstrated between ectopically expressed proteins in COS-7 cells. We have shown that anti-MS-KIF18A antibody immunoprecipitated the ERα and pERK in cells challenged with 17β-estrogen (17β-E2). The hormone activation induced mitogen-activated protein kinases (MAPK) pathway and increased p-ERK. The activation was interfered when cells were pre-treated with either ICI-182,780 or MAPK inhibitor PD98059 prior the challenge with 1 7β-E2 that resulted in a decrease in association between MS-KIF18A and p-ERK1/2. The obtained results suggest a role for the proteins in a non-genomic response of MBA-15 cells challenged with 17β-E2. This study presents a novel interaction between MS-KIF18A and ER that may have important physiological and pharmacological implications for estrogen action in various cells.