Ubiquitin-like protein 3 (UBL3)

Ubiquitin-like protein 3 (UBL3) is a small, highly conserved membrane-anchored protein classified as a ubiquitin-like modifier. UBL3 plays a critical role in the post-translational sorting of specific proteins—including Ras, tubulin, and α-synuclein—into small extracellular vesicles (sEVs, or exosomes). This membrane localization depends on prenylation, and UBL3 physically interacts with a large number of proteins through its C-terminal cysteine residues[1][3]. In the immune system, UBL3 acts as an essential co-factor for the MARCH1 E3 ubiquitin ligase, promoting ubiquitination and plasma membrane trafficking of major histocompatibility complex class II (MHC II) and CD86, which are key regulators of adaptive immunity and antigen presentation[2]. Loss of UBL3 disrupts immune homeostasis, impairs regulatory T cell development, alters dendritic cell populations, and leads to immune signaling changes. UBL3 also interacts with α-synuclein and is implicated in neurodegenerative pathology through its role in vesicular trafficking and potential mediation of protein aggregation and clearance[3]. There are currently no known drugs targeting UBL3, nor is it considered a direct therapeutic target or clinical biomarker, but its fundamental role in vesicle biology and immunity points to possible relevance in a range of diseases. **Note:** - UBL3 is *not* a receptor, enzyme, transporter, or classic therapeutic target but is a membrane-anchored ubiquitin-like protein modifier involved in protein trafficking and immunity. - There are currently no drugs known to directly target UBL3 or established safety concerns related to its manipulation. - Current research highlights roles in immunity, neurodegeneration, and cancer, but it is not an established clinical biomarker or target[1][2][3][4][5].

Other names

UBL3PNSC1HsMUBMUBHCG-1DKFZP434K151FLJ32018Membrane-anchored ubiquitin-fold proteinProtein HCG-1