PINX1

PIN2/TERF1-interacting telomerase inhibitor 1, also known as PINX1, is a human gene.PINX1 is also known as PIN2 interacting protein 1.PINX1 is a telomerase inhibitor and a possible tumor suppressor.

Interactions

PINX1 has been shown to interact with MCRS1,TERF1 and telomerase reverse transcriptase.

Structure

There are two known variants of PINX1. The second variant “lacks an exon in the 3’ coding region which results in a frameshift compared to variant 1. The encoded isoform is shorter and has a distinct C-terminus compared to isoform 1.” There are three PINX1 cDNA clones. The longest one encodes a 328 amino acid 45kDa protein which contains an N-terminal Gly-rich patch and a C-terminal TID domain (telomerase inhibitory domain). The TRF1 binding domain is in the C-terminal 75 amino acids of PINX1. Mouse PINX1 is 74% identical to human PINX1. In other eukaryotes, including yeast, there is an overall 50% similarity to human PINX1.

Function

Over-expression of PINX1 results in decreased telomerase activity, telomere shortening, and induction of crisis. Reduction of PINX1 leads to an increase in telomerase activity and elongation of telomeres. PINX1 differs from other proteins that regulate telomere length in that it acts on telomerase while other proteins adjust telomere length without affecting telomerase activity.