MAP2K1 phosphorylates MAPK3

MAP2K1 (also known as MEK1) phosphorylates the critical Thr202 and Tyr204 on MAPK3 (ERK1), converting two ATP to ADP. Phosphorylation of MAPK3 activates its kinase activity.<p>MAP2K1 activation requires the phosphorylation of two serine residues (S218 and S222) in the activation loop.

MAP2K1（亦称MEK1）磷酸化MAPK3（ERK1）上的关键Thr202和Tyr204位点，将两个ATP转化为ADP。MAPK3的磷酸化激活其激酶活性。MAP2K1的激活需要对其活化环中的两个丝氨酸残基（S218和S222）进行磷酸化。