Digitala Vetenskapliga Arkivet

Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
tPA-GFP is a reliable probe for detecting compound exocytosis in human pancreatic β-cells
Indian Inst Sci IISc, Dept Dev Biol & Genet DBG, Bengaluru, Karnataka, India..
Indian Inst Sci, Mol Biophys Unit, Bengaluru, Karnataka, India.;Indian Inst Sci, Ctr Infect Dis Res, Bengaluru, Karnataka, India..
Indian Inst Sci IISc, Dept Dev Biol & Genet DBG, Bengaluru, Karnataka, India..
Indian Inst Sci, Mol Biophys Unit, Bengaluru, Karnataka, India.;Indian Inst Sci, Ctr Infect Dis Res, Bengaluru, Karnataka, India..
Show others and affiliations
2025 (English)In: FASEB BioAdvances, E-ISSN 2573-9832, Vol. 7, no 2, article id e1482Article in journal (Refereed) Published
Abstract [en]

Pancreatic β-cells secrete insulin stored in large dense core vesicles (LDCV) by fusion of vesicle and plasma membrane during a process called insulin exocytosis. Insulin secretion is biphasic with a fast first phase and a sustained second phase. Previous studies have pointed out that exocytosis of insulin can occur via (1) single LDCVs fusing with the plasma membrane to release their content or (2) multiple vesicles are involved during a process called compound exocytosis. Compound exocytosis represents a specialized form of secretion in which vesicles undergo homotypic fusion either before (multi-vesicular exocytosis) or continuous fusion in a sequential manner from (sequential exocytosis) within the same site at the plasma membrane. We see that the number of multi-vesicles is few and not localized in the vicinity of the plasma membrane. Studying the kinetics of this process and correlating it with biphasic insulin secretion is not possible since there are no specific probes to detect them. It is challenging to identify compound exocytosis with probes that exist for simple exocytosis. To advance our understanding, we need a fluorescent probe that could detect secretory vesicles undergoing compound exocytosis and allow us to distinguish it from other modes of exocytosis. Here, we used two cargo proteins (NPY and tPA) labeled with different fluorescent proteins (mCherry GFP and eGFP) and employed total internal reflection fluorescence microscopy (TIRF-M) to capture distinct single-granule and multi-granular fusion events. We identified tPA-GFP as a better probe for studying compound exocytosis, as it can detect both simple and sequential exocytosis reliably. Using these probes, we have studied the kinetics of compound exocytosis in human β-cells. These observations, with additional experiments, may open a whole new field to study the impact of compound exocytosis on biphasic secretion of insulin. Identifying targets to increase the compound exocytosis process can help potentiate insulin secretion in diabetics.

Place, publisher, year, edition, pages
The Federation of American Societies for Experimental Biology , 2025. Vol. 7, no 2, article id e1482
Keywords [en]
exocytosis, insulin granules, large dense core vesicles, total internal reflection fluorescence microscopy
National Category
Analytical Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-555149DOI: 10.1096/fba.2024-00131ISI: 001383672800001PubMedID: 39917393Scopus ID: 2-s2.0-85213535880OAI: oai:DiVA.org:uu-555149DiVA, id: diva2:1954436
Available from: 2025-04-24 Created: 2025-04-24 Last updated: 2025-04-24Bibliographically approved

Open Access in DiVA

fulltext(6756 kB)20 downloads
File information
File name FULLTEXT01.pdfFile size 6756 kBChecksum SHA-512
1fafcc244ec99d724b62b7e0fa8cea2293a41c09b777e3df254901e975ad87dc65b5aa5a5c7129950ac20a97e95443aa44450953a99658a2285f0f4f51455380
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMedScopus

Search in DiVA

By author/editor
Gandasi, Nikhil R.
By organisation
Department of Medical Cell Biology
Analytical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 20 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 49 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf