Analysis of Tripeptidyl Peptidase 1 in Neuronal Ceroid Lipofuscinosis – CLN2

Neuronal Ceroid Lipofuscinosis (NCL) is a group of 14 different lysosomal storage disorders classified as CLN1-CLN14. These disorders are genetically rare and affect 2-4 individuals out of 100,000. Most NCL disorders are autosomal recessive and cause blindness, seizures, loss of motor coordination, cognitive decline, and a buildup of auto fluorescent storage material in the lysosome. CLN2 is one NCL disorder caused by a genetic mutation in the CLN2 gene that encodes Tripeptidyl Peptidase 1 (TPP1). CLN2’s age of onset is between 2-4 years old and is fatal by late teenage years. TPP1 is a lysosomal protease enzyme that cleaves tripeptides off the N-terminus of its substrates with a Ser-Glu-Asp catalytic triad. There are few reported interacting proteins resulting in TPP1’s substrates and mechanism of regulation to be mostly unknown. Currently, recombinant enzyme therapy and gene therapy are potentially powerful therapeutics against CLN2 but are not a complete cure on their own. The goal of this research was to develop a reliable method of studying the protein-protein interactions of TPP1 to further understand its substrates and mechanism of regulation to aid future discovery and development of therapeutic drug targets to improve the quality of life of patients affected with CLN2. A BioID labeling system and Co-Immunoprecipitation approach were utilized to isolate and identify potential binding partners of TPP1. The BioID system successfully identified potential TPP1 interacting proteins while the Co-immunoprecipitation approach successfully isolated TPP1 but lacked an adequate level of TPP1 in the sample to be recoded via mass spectrometry.

For more information email: ljmontor@eckerd.edu