Ubiquilin 2

Ubiquilin 2, also known as UBQLN2, PLIC2 and Chap1, is a member of the ubiquilin protein family, which regulate the degradation of cellular proteins through proteasome or autophage-like pathways. Humans have four ubiquilin genes, each encoding a separate protein referred to as Ubiquilin 1, 2, 3 and 4. All ubiquilins contain an N-terminal ubiquitin-like (UBL) domain and a C-terminal ubiquitin-associated (UBA) domain, while the central part of the molecules are highly variable.

Teepu Siddique and his collaborators have identified mutations in the ubiquilin 2 gene leading to protein point mutations which were important contributors to several forms of amyotrophic lateral sclerosis (ALS) and Frontotemporal lobar degeneration (FTLD). Interestingly, these mutations involved alterations in proline residues in the PXX repeat region (P497H, P497S, P506T, P509S and P525S*). Recently, the Lee and Trojanowski group investigated C9orf72 hexanucleotide expansion and ubiquilin 2 pathology in patients with ALS and FTLD by genetic analysis and immunohistochemistry and found distinct ubiquilin 2 pathology in ALS and FTLD-TDP with C9orf72 expansion.** *Nature Aug 21;477(7363):211-5 2011). **Acta Neuropathol. Jun;123 (6):825-39 2012.