IMMUNOLOGY2026™ Conference Recordings For Attendees-UVRAG and the VPS34 complex II regulate macropinocytosis via the synthesis of PI(3)P on the plasma membrane

UVRAG and the VPS34 complex II regulate macropinocytosis via the synthesis of PI(3)P on the plasma membrane

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Video Summary

The speaker, a PhD student at South Dakota State University, presented research on micropinocytosis in macrophages, focusing on PI3P signaling. Micropinocytosis is a cell “drinking” process where macrophages take up extracellular fluid. Using live-cell imaging and CRISPR screening, the lab found that the class III PI3 kinase complex VPS34/UVRAG promotes micropinocytosis by generating PI3P, while class I and class III PI3 kinase act independently. UVRAG localized to nascent micropinosomes, and loss of UVRAG reduced PI3P levels and dye uptake. They also found evidence that PI3P appears early at the plasma membrane and may involve a small Rab5-positive vesicle. Rab5 and its effectors positively regulated micropinocytosis. In contrast, PAK2 acted as a negative regulator, likely by affecting Rab5 effector phosphorylation. Overall, the study identifies new positive and negative regulators of macrophage micropinocytosis.

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Date April 17, 2026 9:15 AM - 9:30 AM

Room 156

Session Mechanisms of Innate Immunity

Speaker Astha Neupane

Track Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)

Year 2026

Keywords

micropinocytosis

macrophages

PI3P signaling

VPS34 UVRAG

Rab5 regulation

April 17, 2026 9:15 AM - 9:30 AM

156

Mechanisms of Innate Immunity

Astha Neupane

Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)

2026