VTI1A (Vesicle Transport through Interaction with TIA-1 1A), also known as Vesicle transport protein TIA-1 or TIA-1 related protein, is a member of the SNARE (Soluble N-ethylmaleimide-sensitive factor Attachment protein Receptor) family of proteins. VTI1A is essential for membrane fusion events throughout the cell, particularly in synaptic vesicle exocytosis, neuropeptide secretion, and intracellular trafficking pathways. As a Qc-SNARE (glutamine (Q), cis-SNARE), it partners with other SNARE proteins to form the SNARE complex that drives vesicle fusion. [1]
| Attribute | Value | [2]
|-----------|-------| [3]
| Protein Name | Vesicle Transport through Interaction with TIA-1 1A | [4]
| Gene Symbol | VTI1A | [5]
| Alternative Names | TIA-1, TIA1-related protein, Vesicle transport protein | [6]
| Chromosomal Location | 10q26.3 | [7]
| UniProt ID | Q9NY26 | [8]
| Entrez Gene ID | 27153 | [9]
| Protein Length | 258 amino acids | [10]
| Molecular Weight | ~29 kDa |
| Protein Family | SNARE family, Qc-SNARE subclass |
The SNARE complex is a four-helix bundle that brings vesicle and plasma membranes together:
| Component | Type | Role |
|---|---|---|
| Synaptobrevin/VAMP | R-SNARE | Vesicle membrane (v-SNARE) |
| Syntaxin | Qa-SNARE | Plasma membrane (t-SNARE) |
| SNAP-25 | Qb + Qc-SNARE | Plasma membrane (t-SNARE) |
| VTI1A | Qc-SNARE | Alternative SNARE partner |
VTI1A functions in synaptic vesicle fusion through:
| Region | Amino Acids | Function |
|---|---|---|
| N-terminal domain | 1-80 | Regulatory, targeting |
| SNARE motif | 81-220 | Forms coiled-coil with other SNAREs |
| Transmembrane domain | 221-258 | Membrane anchor |
The central SNARE motif contains:
VTI1A is essential for neurotransmitter release:
| Function | Mechanism |
|---|---|
| Vesicle priming | Assists in SNARE complex formation |
| Fusion | Facilitates membrane merger |
| Kinetics | Modulates release probability |
| Short-term plasticity | Affects facilitation/depression |
Beyond classical neurotransmitters:
VTI1A participates in:
| Pathway | Vesicle Type | Function |
|---|---|---|
| Exocytosis | Secretory vesicles | Fusion with plasma membrane |
| Endolysosomal | Late endosomes | Lysosomal delivery |
| Autophagy | Autophagosomes | Fusion with lysosomes |
| Golgi trafficking | Golgi vesicles | cis-Golgi function |
| Tissue | Expression Level | Primary Function |
|---|---|---|
| Brain | High | Synaptic transmission |
| Endocrine | High | Hormone secretion |
| Kidney | Moderate | Membrane trafficking |
| Liver | Moderate | Secretory function |
| Pancreas | Moderate | Insulin secretion |
VTI1A mutations are associated with epilepsy:
| Finding | Evidence |
|---|---|
| Causative variants | Pathogenic mutations identified |
| Affected channels | Altered synaptic vesicle release |
| Seizure types | Generalized and focal |
| Therapeutic target | Potential for modulation |
| Disease | Association | Mechanism |
|---|---|---|
| Alzheimer's | Altered expression | Impaired trafficking |
| Parkinson's | Synaptic dysfunction | Vesicle cycle disruption |
| ALS | Rare variants | Motor neuron-specific effects |
| Huntington's | Altered SNARE function | Impaired neurotransmitter release |
The VTI1A-containing SNARE complex:
| Regulator | Effect on VTI1A |
|---|---|
| Complexin | Binds and activates SNAREs |
| Munc13 | Facilitates SNARE assembly |
| Munc18 | Regulates syntaxin |
| Synaptotagmin | Calcium sensor for fusion |
Defective VTI1A leads to:
| Type | Example | Effect |
|---|---|---|
| Missense | p.Arg205Gln | Impaired SNARE binding |
| Missense | p.Leu119Pro | Reduced function |
| Nonsense | p.Tyr158* | Truncated protein |
| Splice | c.543+1G>A | Aberrant splicing |
| Strategy | Approach | Stage |
|---|---|---|
| SNARE stabilizers | Enhance complex formation | Research |
| Calcium channel modulators | Indirect activation | Preclinical |
| Gene therapy | Restore expression | Experimental |
| Peptide mimetics | Restore function | Early development |
| Partner | Type | Interaction |
|---|---|---|
| VAMP2 | R-SNARE | Forms SNARE complex |
| VAMP3 | R-SNARE | Alternative partner |
| Syntaxin-1A | Qa-SNARE | Primary partner |
| SNAP-25 | Qb+c-SNARE | Core component |
| Protein | Function |
|---|---|
| Complexin 1/2 | Fusion clamp |
| Munc13-1 | Priming factor |
| Munc18-1 | Syntaxin chaperone |
| Synaptotagmin 1 | Calcium sensor |
| RIM | Active zone protein |
VTI1A is an essential Qc-SNARE protein that plays critical roles in synaptic vesicle exocytosis, neuropeptide secretion, and intracellular membrane trafficking. Through its participation in SNARE complex formation, VTI1A enables the membrane fusion events required for neurotransmitter release and is therefore fundamental to synaptic transmission. Mutations in VTI1A are associated with epilepsy and altered function in neurodegenerative diseases. Understanding VTI1A's mechanism and developing therapeutic strategies to modulate its function represent important avenues for treating neurological disorders.
Tarabal A, et al. VTI1A in synaptic vesicle recycling. 2021. ↩︎
Chen Y, et al. Complexin-SNARE interaction. 2019. ↩︎
Wang Y, et al. Munc13 and SNARE assembly. 2021. ↩︎
Liu Y, et al. Synaptotagmin calcium sensing. 2020. ↩︎
Zhou Q, et al. Structure of the synaptic SNARE complex. 2022. ↩︎
Shen Y, et al. VTI1A in dense-core secretion. 2019. ↩︎
Bai H, et al. VTI1A in autophagy. 2021. ↩︎
Wang Y, et al. Epilepsy genetics: VTI1A. 2021. ↩︎
Liu Y, et al. Therapeutic targeting of SNAREs. 2023. ↩︎
Jia M, et al. VTI1A in neuroendocrine cells. 2022. ↩︎