VIP36 protein is a target of ectodomain shedding and regulates phagocytosis in macrophage Raw 264.7 cells

Area of Science:

• Cell Biology
• Immunology
• Proteomics

Background:

• Ectodomain shedding is a posttranslational modification releasing extracellular protein domains.
• This process, primarily mediated by ADAM metalloproteases, has multifaceted effects but incompletely understood physiological roles.
• Understanding shedding's function is crucial for elucidating cellular communication and immune responses.

Purpose of the Study:

• To identify novel ectodomain shedding targets in macrophages using unbiased proteomic screening.
• To elucidate the immunological function of ectodomain shedding.
• To investigate the role of VIP36 shedding in macrophage function.

Main Methods:

• Unbiased proteomic screening of lipopolysaccharide (LPS)-stimulated macrophage cell line.
• Identification and characterization of VIP36 as a shedding target.
• Assessment of VIP36 levels and shedding's impact on macrophage phagocytosis.

Main Results:

• VIP36 (vesicular integral membrane protein 36) was identified as a novel ectodomain shedding target.
• VIP36 shedding occurs predominantly on the cell surface.
• The quantity of VIP36 directly regulates macrophage phagocytosis, and its shedding is essential for this regulation.

Conclusions:

• VIP36 shedding is a newly discovered mechanism regulating macrophage phagocytosis.
• This finding expands the understanding of VIP36's function beyond intracellular transport.
• The study highlights a novel immunological role for ectodomain shedding and VIP36.