The CAPS1 protein was initially discovered as a cytosolic soluble 145kDa protein which was necessary to restore calcium dependent norephinephrine secretion in cracked PC12 cells. Recent findings suggest that CAPS may also play a role in synaptic and dense core vesicle exocytosis as well as in the loading of monoamine neurotransmitters. Recently, studies have implicated CAPS1 in the binding to syntaxin-1. However, no studies have identified the key residues of CAPS1 that facilitate this interaction with syntaxin-1. I show that the binding mode of CAPS1 is independent from that of Munc13 such that CAPS1 requires the full length of syntaxin-1 to bind. Moreover, CAPS1 favors the open conformation of syntaxin-1. Interestingly, the Munc homology (MH) domain of CAPS1 is not critical for this interaction while the C-terminal dense core vesicle binding (DCVB) domain plays an important role. Moreover, truncations to this DCVB domain result in decreased binding to syntaxin-1.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/31381 |
| Date | 19 December 2011 |
| Creators | Parsaud, Leon |
| Contributors | Sugita, Shuzo |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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