As an essential component of the MAP kinase signal transduction pathway, this kinase is involved in many cellular processes such as proliferation, differentiation, transcription regulation and development.

[8] The genomes of diploid organisms in natural populations are highly polymorphic for insertions and deletions.

MEK1 is a meiotic chromosome-axis-associated kinase that is thought to slow down, but not entirely block, sister chromatid recombination.

Despite the normal activity of MEK1 in reducing inter-sister chromatid recombination, such recombination still occurs frequently during normal budding yeast meiosis (although not as frequently as during mitosis), and up to one-third of all recombination events are between sister chromatids.

[9] MAP2K1 has been shown to interact with C-Raf,[10] Phosphatidylethanolamine binding protein 1,[10] MAP2K1IP1,[11][12] GRB10,[13] MAPK3,[12][14][15][16] MAPK8IP3,[17][18] MAPK1[10][11][19][20][21][22] MP1,[12] and MAP3K1.