This enzyme phosphorylates and activates its downstream protein kinase, EC 184.108.40.206, mitogen-activated protein kinase kinase (MAPKK) but requires MAPKKKK for activation. Some members of this family can be activated by p21-activated kinases (PAK/STE20) or Ras. While c-Raf and c-Mos activate the classical MAPK/ERK pathway, MEKK1 and MEKK2 preferentially activate the c-Jun N-terminal protein kinase(JNK)/stress-activated protein kinase (SAPK) pathway . Mitogen-activated protein kinase (MAPK) signal transduction pathways are among the most widespread mechanisms of cellular regulation. Mammalian MAPK pathways can be recruited by a wide variety of stimuli including hormones (e.g. insulin and growth hormone), mitogens (e.g. epidermal growth factor and platelet-derived growth factor), vasoactive peptides (e.g. angiotensin-II and endothelin), inflammatory cytokines of the tumour necrosis factor (TNF) family and environmental stresses such as osmotic shock, ionizing radiation and ischaemic injury.
disruption of MCK1 resulted in the fungus undergoing autolysis and showing hypersensitivity to cell-wall-degrading enzyme, mutant strain produces significantly reduced numbers of conidia and developed appressoria in a slightly retarded manner compared with the wild type, mutant is unable to penetrate into plant tissues
; native and mutant mice, mutant embryos are growth retarded and die in utero; normal and mutant mice, mutant mice appear normal at birth but die 7-21 days postpartum due to neurological and intestinal problems; normal and mutant mice, mutant mice die in utero due to severe vascular abnormalities