Analysis of Erk1
For my lab analysis, I was assigned the protein code ERK1 which stands for Extracellular Signal-regulated Kinases that belongs to the family of Mitrogen-activated proteins (MAP). They are mostly involved in signaling of several cellular activities.For example they are involved in processes of differentiation, cell cycle and proliferation. Upstream kinases activate ERK1 which in turn results into change in position going towards nucleus in which it phosphorylates a particular place in the nucleus.In addition ERK1 alongside ERK2 are involved in Ras-Raf-MEK-ERK signal transduction cascade. This form of cascade plays a role in many body processes such as cell cycle progression, cell migration, cell adhesion, metabolism, proliferation, differentiation and cell transcription.ERK1 and ERK2 are also involved in catalysis and phosphorylation of very many nucleus substrates and cytoplasmic which involves transcription and regulatory molecule (Lawrence et al. 12 – 14).
ERK1 is involved in proline-directed kinases catalyzing the phosphorylation at the first stage of substrates that possess Pro-Xxx-Ser/Thr-Pro sequence. Most ERK1 contains F-Docking and D-Docking sites or a combination of both of them.The isoform ERK1 and isoform ERK2 have similar amino-acids sequences but have different physiological purposes. When ERK1 is auto and mono phosphorylated at Tyr204 in the activation loop during Escherichia coli production it has a basal activity level that is far much less than that of a fully active or dual-phosphorylated ERK1 by Thr204 and Thr202. The basal activity of mono-phosphorylated ERK1 is caused by the structural nature of the C-helix and that of the activation loop. The crystal structure of Mono-phosphorylated and dual-phosphorylated ERK1 are different and distinguishable. ERK1 has several inhibitors binding sites for example the D-motif and the backside binding site (Kinoshita et al. 1125 – 1126).
Therefore, ERK1 is a protein serine/threonine kinase and as earlier mentioned is involved in signal transduction.The difference in structure to the adult hemoglobin is that ERK1 structure proves that it is able to have a higher affinity for oxygen than that of adult hemoglobin. The second difference in their structure is that the structure of adult hemoglobin has an alpha and a gamma particle while the structure of ERK1 has a beta particle but lacks both alpha and gamma particles.However there exist some similarities between the ERK1 and the adult hemoglobin structure in that both have a protein structure in them. However hemoglobin plays its role on a macro level cell processes while ERK1 plays a role in microscopic nucleus and cell processes.This means that ERK1 also plays a role in adult hemoglobin nucleus processes such as catalyzing the transduction signal process,cell adhesion and cell movement (Wilber, Nienhuis and Persons 3946). Another similarity between the structure of ERK1 and fetal hemoglobin is the existence of better sequence in both of these structures although the adult hemoglobin has gamma-delta-globin sequence.
Answer to question five.
Exposure of ERK1 to more than the recommended body temperature of approximated above 4 and an exposure of 120 minutes makes its structure to change by denaturing it just like any other enzyme and therefore ERK1 is very sensitive to heat denaturation. However, cytokines and stress stimuli when subjected to ERK1 alter its regulation path. When ERK is subjected to a heat stroke and IL3-dependent proB cell and Baf3 used to determine if the ERK1 has been activated. The result shows that at about 420c phosphorylation of ERK1 occurs and is active at this temperature and exposure time. The stimulation of phosphorylation of ERK1 due to heat shock is more than that caused by other stress stimuli such as oxidative stress, osmotic shock or use of cytokines (Ruotsalainen and Savolainen 267 – 268).
Wilber, A., Nienhuis, A. and Persons, D. (2011). Transcriptional regulation of fetal to adult hemoglobin switching: new therapeutic opportunities. Blood, 117(15), 3945-3953.
Kinoshita, Takayoshi et al. “Crystal Structure Of Human Mono-Phosphorylated ERK1 At Tyr204”. Biochemical and Biophysical Research Communications 377.4 (2008): 1123-1127. Web.
Ruotsalainen, M., and K. M Savolainen. “Effects Of A Protein Kinase C Inhibitor, Ro 31-7549, On The Activation Of Human Leuko Cytes By Particulate Stimuli”. Human & Experimental Toxicology14.3 (1995): 266-272.
Lawrence, M. et al. “The Protein Kinases ERK1/2 and their Roles in Pancreatic Beta Cells”.Acta Physiologica 192.1 (2007): 11-17. Web.