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Structure
PTEN is a protein that consists of 403-amino acids. Breaking it down into two main parts (the C-terminal and the N-terminal) it has 166 residues on the C-terminal (C2 Domain) and 179 on the N-terminal (Phosphatase Domain). PTEN is consisted of Alpha helix and Beta pleated sheets. PTEN has a signature motif that forms a Walker loop (Phosphate-bonding loop) HCXXGXXR which is residues 123-130. The pocket of PTEN is about 8 angstroms deep. There are Cys, Arg, His, and Gly within the Walker loop. His and Gly are both important for the Walker loop, while the Cys and Arg are important for the catalytic ability of the PTEN enzyme. One difference from PTEN compared to other know Protein Tyrosine Phosphatases (PTPs) is the location of two Lys residues in the center of the Walker Loop.
Function
PTEN is a dual phosphatase and tumor suppressor protein that interacts with LKB-1. It is composed of a C-terminal and N-Terminal. The C-Terminal is a C2 Domain, this targets proteins to cell membranes. The N-terminal is a Phosphatase Domain, it’s job is to remove phosphate groups from a phosphorylated amino acid.
Disease
The protein is located on the 10th chromosome 10q23.31 in humans. PTEN works with tumor suppressing for cancers, such as breast and prostate cancer. It also works to remove phosphate groups from specific amino acids, such as dephosphorylating tyrosine, serine, and threonine phosphorylated peptides.
Relevance
PTEN’s relevance is that without the PTEN suppressing tumors, you would have a higher increased odds of having multiple cancers, including but not limited to Breast and Prostate cancer. PTEN is one of the enzymes tested for when someone has their genes tested. The user is being testing for Hereditary cancer risk when looking at the portion of the genome containing PTEN.
Structural highlights
PTEN’s main structural points is the N and C terminal along with the Walker loop containing the Cys, His, Arg, and Gly making it stand out.
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References
1. Crystal Structure of the PTEN Tumor Suppressor
Lee, Jie-Oh et al.
Cell , Volume 99 , Issue 3 , 323 - 334
2. Lee, et al. ?Crystal Structure of the PTEN Tumor Suppressor: Implications for Its Phosphoinositide Phosphatase Activity and Membrane Association.? Acta Crystallogr.,Sect.D, www.rcsb.org/structure/1D5R.
3. Lumb, Craig N., and Mark S.P. Sansom. ?PTEN.? Advances in Pediatrics., U.S. National Library of Medicine, 5 Feb. 2013, www.ncbi.nlm.nih.gov/pmc/articles/PMC3566463/.
4. Mehenni, et al. ?LKB1 Interacts with and Phosphorylates PTEN: a Functional Link between Two Proteins Involved in Cancer Predisposing Syndromes | Human Molecular Genetics | Oxford Academic.? OUP Academic, Oxford University Press, 29 June 2005, academic.oup.com/hmg/article/14/15/2209/551725.
5. ?PTEN Gene - Genetics Home Reference.? U.S. National Library of Medicine, National Institutes of Health, ghr.nlm.nih.gov/gene/PTEN.
