Abstract
RING Finger Protein 167 (RNF167) is an E3 ubiquitin ligase and a key regulator of
lysosomal trafficking. Dysfunctional lysosomes are associated with neurodegenerative
disorders and can cause numerous lysosomal storage diseases; thus, it is essential to
understand how lysosomes are regulated. There is currently very little research
surrounding how RNF167 regulates lysosomes in neurons. A natural isoform, RNF167b,
has also been reported, which lacks a signal peptide; the function of this isoform is yet to
be studied in neurons. The aim of the current study was to investigate the role of
RNF167a and b within neurons, by determining whether each isoform is localised to
lysosomes as well as investigating whether RNF167a and b are involved in lysosomal
function. RNF167a and b with and without fluorescent tags were cloned into lentiviral
plasmids and packaged into lentivirus, before being transduced into neurons.
Fluorescently tagged RNF167 was used to visualise localisation with lysosomes, while
functional assays using RNF167 overexpression constructs were performed to investigate
lysosomal acidity and cathepsin B activity. It was found that RNF167a was more highly
localised to lysosomes compared to RNF167b. RNF167a was also shown to influence
lysosomal function, while RNF167b did not. This implied that RNF167a is likely a key
regulator of lysosomal function. RNF167b however, may instead be involved in other
neuronal processes unrelated to lysosomes which should be examined further.