VAMP2 is implicated in the secretion of antibodies by human plasma cells and can be replaced by other synaptobrevins.
The production and secretion of antibodies by human plasma cells (PCs) are two essential processes of humoral immunity. The secretion process relies on a group of proteins known as soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), which are located in the plasma membrane (t-SNAREs) and in the antibody-carrying vesicle membrane (v-SNARE), and mediate the fusion of both membranes. We have previously shown that SNAP23 and STX4 are the t-SNAREs responsible for antibody secretion. Here, using human PCs and antibody-secreting cell lines, we studied and characterized the expression and subcellular distribution of vesicle associated membrane protein (VAMP) isoforms, demonstrating that all isoforms (with the exception of VAMP1) are expressed by the referenced cells. Furthermore, the functional role in antibody secretion of each expressed VAMP isoform was tested using siRNA. Our results show that VAMP2 may be the v-SNARE involved in vesicular antibody release. To further support this conclusion, we used tetanus toxin light chain to cleave VAMP2, conducted experiments to verify co-localization of VAMP2 in antibody-carrying vesicles, and demonstrated the coimmunoprecipitation of VAMP2 with STX4 and SNAP23 and the in situ interaction of VAMP2 with STX4. Taken together, these findings implicate VAMP2 as the main VAMP isoform functionally involved in antibody secretion.
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Laura
L
Gómez-Jaramillo
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Raquel
R
Romero-García
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Gema
G
Jiménez-Gómez
Department of Biology, Ball State University, Muncie, IN, USA.
Lisa
L
Riegle
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Ana Belén
AB
Ramos-Amaya
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain.
José Antonio
JA
Brieva
Department of Biology, Ball State University, Muncie, IN, USA.
Marie
M
Kelly-Worden
Unidad de Investigación, Hospital Universitario Puerta del Mar, Cádiz, Spain. antonio.campos.caro.sspa@juntadeandalucia.es.
Antonio
A
Campos-Caro
D000906:Antibodies / Q000378:metabolism*; D002460:Cell Line; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D020868:Gene Silencing; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D010950:Plasma Cells / Q000378:metabolism*; D000072417:Protein Domains; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000378:metabolism; D050766:Qb-SNARE Proteins / Q000378:metabolism; D050767:Qc-SNARE Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013744:Tetanus Toxin / Q000378:metabolism; D050988:Vesicle-Associated Membrane Protein 2 / Q000737:chemistry / Q000378:metabolism*
D000906:Antibodies; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D034741:RNA, Small Interfering; C100493:SNAP23 protein, human; D013744:Tetanus Toxin; D050988:Vesicle-Associated Membrane Protein 2; C587292:syntaxin 4, human; D007073:Immunoglobulin E
VAMP proteins; exocytosis; human; immunoglobulin; plasma cells