LNX1/LNX2 proteins: functions in neuronal signalling and beyond

Area of Science:

• Molecular Biology
• Neuroscience
• Cell Biology

Background:

• Ligand of NUMB Protein X1 and X2 (LNX1/2) are E3 ubiquitin ligases.
• They interact with and degrade the cell fate determinant NUMB, influencing NUMB/NOTCH signaling in neurogenesis.
• LNX1/2 proteins bind numerous other proteins via PDZ domains, suggesting broader functions.

Purpose of the Study:

• To discuss the putative neuronal functions of LNX1/2 proteins.
• To review known non-neuronal roles of LNX1/2 proteins.
• To consider LNX1/2 functions in light of anxiety-related phenotypes in knockout mice.

Main Methods:

• Review of existing literature on LNX1/2 protein functions.
• Analysis of phenotypes in double knockout mice lacking LNX1 and LNX2 in the CNS.
• Examination of roles in embryonic patterning, pancreas development, colorectal cancer, osteoclast differentiation, and immune function.

Main Results:

• LNX1/2 proteins are implicated in synapse formation, neurotransmission, and neuroglial function.
• Knockout mice lacking LNX1 and LNX2 exhibit anxiety-related phenotypes.
• Non-neuronal roles include embryonic patterning, pancreas development, colorectal cancer, osteoclast differentiation, and immune function.

Conclusions:

• LNX1/2 proteins are potential regulators of multiple cellular signaling pathways.
• The physiological significance of many LNX1/2 roles requires further validation.
• Tight control of LNX1/2 protein levels in vivo is crucial for understanding their functions.