Next Article in Journal
Anabolic Factors and Myokines Improve Differentiation of Human Embryonic Stem Cell Derived Skeletal Muscle Cells
Previous Article in Journal
Oxidative Stress and AKT-Associated Angiogenesis in a Zebrafish Model and Its Potential Application for Withanolides
 
 
Article

Early Endosomal Vps34-Derived Phosphatidylinositol-3-Phosphate Is Indispensable for the Biogenesis of the Endosomal Recycling Compartment

1
Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia
2
Department of Physiology, Immunology and Pathophysiology, Faculty of Medicine, University Center Varaždin, University North, Jurja Križanića 31b, 42000 Koprivnica, Croatia
3
Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia
*
Author to whom correspondence should be addressed.
Academic Editor: Cord Brakebusch
Cells 2022, 11(6), 962; https://doi.org/10.3390/cells11060962
Received: 18 January 2022 / Revised: 17 February 2022 / Accepted: 9 March 2022 / Published: 11 March 2022
Phosphatidylinositol-3-phosphate (PI3P), a major identity tag of early endosomes (EEs), provides a platform for the recruitment of numerous cellular proteins containing an FYVE or PX domain that is required for PI3P-dependent maturation of EEs. Most of the PI3P in EEs is generated by the activity of Vps34, a catalytic component of class III phosphatidylinositol-3-phosphate kinase (PI3Ks) complex. In this study, we analyzed the role of Vps34-derived PI3P in the EE recycling circuit of unperturbed cells using VPS34-IN1 (IN1), a highly specific inhibitor of Vps34. IN1-mediated PI3P depletion resulted in the rapid dissociation of recombinant FYVE- and PX-containing PI3P-binding modules and endogenous PI3P-binding proteins, including EEA1 and EE sorting nexins. IN1 treatment triggered the rapid restructuring of EEs into a PI3P-independent functional configuration, and after IN1 washout, EEs were rapidly restored to a PI3P-dependent functional configuration. Analysis of the PI3P-independent configuration showed that the Vps34-derived PI3P is not essential for the pre-EE-associated functions and the fast recycling loop of the EE recycling circuit but contributes to EE maturation toward the degradation circuit, as previously shown in Vps34 knockout and knockdown studies. However, our study shows that Vps34-derived PI3P is also essential for the establishment of the Rab11a-dependent pathway, including recycling cargo sorting in this pathway and membrane flux from EEs to the pericentriolar endosomal recycling compartment (ERC). Rab11a endosomes of PI3P-depleted cells expanded and vacuolized outside the pericentriolar area without the acquisition of internalized transferrin (Tf). These endosomes had high levels of FIP5 and low levels of FIP3, suggesting that their maturation was arrested before the acquisition of FIP3. Consequently, Tf-loaded-, Rab11a/FIP5-, and Rab8a-positive endosomes disappeared from the pericentriolar area, implying that PI3P-associated functions are essential for ERC biogenesis. ERC loss was rapidly reversed after IN1 washout, which coincided with the restoration of FIP3 recruitment to Rab11a-positive endosomes and their dynein-dependent migration to the cell center. Thus, our study shows that Vps34-derived PI3P is indispensable in the recycling circuit to maintain the slow recycling pathway and biogenesis of the ERC. View Full-Text
Keywords: phosphatidylinositol-3-phosphate; Vps34; VPS34-IN1; Rab11a endosomes; endosomal recycling compartment phosphatidylinositol-3-phosphate; Vps34; VPS34-IN1; Rab11a endosomes; endosomal recycling compartment
Show Figures

Figure 1

MDPI and ACS Style

Marcelić, M.; Mahmutefendić Lučin, H.; Jurak Begonja, A.; Blagojević Zagorac, G.; Lučin, P. Early Endosomal Vps34-Derived Phosphatidylinositol-3-Phosphate Is Indispensable for the Biogenesis of the Endosomal Recycling Compartment. Cells 2022, 11, 962. https://doi.org/10.3390/cells11060962

AMA Style

Marcelić M, Mahmutefendić Lučin H, Jurak Begonja A, Blagojević Zagorac G, Lučin P. Early Endosomal Vps34-Derived Phosphatidylinositol-3-Phosphate Is Indispensable for the Biogenesis of the Endosomal Recycling Compartment. Cells. 2022; 11(6):962. https://doi.org/10.3390/cells11060962

Chicago/Turabian Style

Marcelić, Marina, Hana Mahmutefendić Lučin, Antonija Jurak Begonja, Gordana Blagojević Zagorac, and Pero Lučin. 2022. "Early Endosomal Vps34-Derived Phosphatidylinositol-3-Phosphate Is Indispensable for the Biogenesis of the Endosomal Recycling Compartment" Cells 11, no. 6: 962. https://doi.org/10.3390/cells11060962

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop