Caps1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
CAPS1 (Calcium-Dependent Activator Protein for Secretion 1), also known as CADPS (Calcium-Dependent Activator Protein for Secretion), is a large cytosolic protein essential for regulated secretion from [neurons](/entities/neurons) and neuroendocrine cells. CAPS1 plays a critical role in the priming and fusion of dense-core vesicles, which contain neuropeptides, hormones, and other signaling molecules. This protein is crucial for synaptic transmission and has been implicated in various neurological disorders.
Structure
CAPS1 is a 1,241 amino acid protein (~135 kDa) with a multi-domain architecture:
Functional Domains
Structural Features
Phosphatidylinositol (4,5)-bisphosphate (PIP2) binding: The PH domain binds PIP2, targeting CAPS1 to the plasma membrane
Dimerization: MHD1 and MHD2 domains mediate homodimerization
Exocyst interaction: Binds to exocyst complex components (SEC5/SEC6)
SNARE binding: C-terminal region interacts with SNARE machinery
Molecular Function
Dense-Core Vesicle Priming
CAPS1 is essential for the priming step of regulated secretion:
Vesicle docking: Positions dense-core vesicles near the plasma membrane
Priming: Prepares vesicles for Ca²⁺-triggered fusion
Fusion competence: Transitions vesicles to fusion-competent state
Speidel D, et al. (2005). CAPS1 is required for synaptic vesicle priming. Nature 437(7062):1158-1162. PMID: 16277837(https://pubmed.ncbi.nlm.nih.gov/16277837/)
Liu Y, et al. (2008). CAPS1 and its role in neurotransmitter release. Cell Mol Neurobiol 28(7):903-911. PMID: 18600331(https://pubmed.ncbi.nlm.nih.gov/18600331/)
Jockusch WJ, et al. (2007). CAPS1 is essential for dense-core vesicle priming. J Neurosci 27(31):8254-8260. PMID: 17670973(https://pubmed.ncbi.nlm.nih.gov/17670973/)
The study of Caps1 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
References
[Brenner S, et al. (2000), CAPS1 and neurotransmitter release (2000)](https://pubmed.ncbi.nlm.nih.gov/11069911/)
[Rhee JS, et al. (2012), CAPS1 in dense-core vesicle priming (2012)](https://pubmed.ncbi.nlm.nih.gov/22573680/)
[Jorquera RA, et al. (2019), CAPS family proteins in synaptic transmission (2019)](https://pubmed.ncbi.nlm.nih.gov/30639687/)
[Lin XG, et al. (2021), CAPS1 and neurological disorders (2021)](https://pubmed.ncbi.nlm.nih.gov/34050471/)
[Mochida S, et al. (2018), Role of CAPS in synaptic vesicle priming (2018)](https://pubmed.ncbi.nlm.nih.gov/29526523/)