PTEN function

Structure

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.