Tailor-Made Protein Tyrosine Phosphatases: In Vitro Site-Directed Mutagenesis of PTEN and PTPRZ-B.

In vitro site-directed mutagenesis (SDM) of protein tyrosine phosphatases (PTPs) is a commonly used approach to experimentally analyze PTP functions at the molecular and cellular level and to establish functional correlations with PTP alterations found in human disease. Here, using the tumor-suppressor PTEN and the receptor-type PTPRZ-B (short isoform from PTPRZ1 gene) phosphatases as examples, we provide a brief insight into the utility of specific mutations in the experimental analysis of PTP functions. We describe a standardized, rapid, and simple method of mutagenesis to perform single and multiple amino acid substitutions, as well as deletions of short nucleotide sequences, based on one-step inverse PCR and DpnI restriction enzyme treatment. This method of SDM is generally applicable to any other protein of interest.

PTEN: a yin-yang master regulator protein in health and disease.

The PTEN gene is a tumor suppressor gene frequently mutated in human tumors, which encodes a ubiquitous protein whose major activity is to act as a lipid phosphatase that counteracts the action of the oncogenic PI3K. In addition, PTEN displays protein phosphatase- and catalytically-independent activities. The physiologic control of PTEN function, and its inactivation in cancer and other human diseases, including some neurodevelopmental disorders, is upon the action of multiple regulatory mechanisms. This provides a wide spectrum of potential therapeutic approaches to reconstitute PTEN activity. By contrast, inhibition of PTEN function may be beneficial in a different group of human diseases, such as type 2 diabetes or neuroregeneration-related pathologies. This makes PTEN a functionally dual yin-yang protein with high potential in the clinics. Here, a brief overview on PTEN and its relation with human disease is presented.