ZF-
I'm kind of getting out of my range here, but let me tell you how I imagine the process:

The binding of antigliadin to Synapsin I prevents neurotransmitter release (exocytosis). The process of exocytosis has been shown to be the trigger which facilitates the dispersion of excess alpha-synuclein from the cell body. If exocytosis is interrupted, excess alpha-synuclein remains in the nerve terminal.
The fibril form of alpha-synuclein is stiff and pointy and pokes holes in the cellular membranes like the nucleus, mitochondria and golgi complex. To protect itself the cell folds it up and covers it with other proteins creating Lewy Bodies. Parkin and ubiquitin are two of the proteins involved in that process. People with parkin mutation don't make Lewy bodies and their cells die faster. It looks like LRRK2 is also one of those "waste processing" proteins, it binds to parkin, and is found in Lewy bodies in the few studies that have been done. LRRK2 mutations result in rapid cell degeneration.

If that sequence is correct, then the goal is the same but more time-critical: to avoid the excess alpha-synuclein in the first place.

I've got a bunch of abstracts in a couple docs here, not very tidy, but I'll send them to you if you want.

-H

ps. Cara has links to lupus articles here. Scroll about halfway down.