Prominin‐1 (CD133) modulates the architecture and dynamics of microvilli

Abstract

Prominin‐1 is a cell surface biomarker that allows the identification of stem and cancer stem cells from different organs. It is also expressed in several differentiated epithelial and non‐epithelial cells. Irrespective of the cell type, prominin‐1 is associated with plasma membrane protrusions. Here, we investigate its impact on the architecture of membrane protrusions using microvilli of Madin‐Darby canine kidney cells as the main model. Our high‐resolution analysis revealed that upon the overexpression of prominin‐1 the number of microvilli and clusters of them increased. Microvilli with branched and/or knob‐like morphologies were observed and stimulated by mutations in the ganglioside‐binding site of prominin‐1. The altered phenotypes were caused by the interaction of prominin‐1 with phosphoinositide 3‐kinase and Arp2/3 complex. Mutation of tyrosine 828 of prominin‐1 impaired its phosphorylation and thereby inhibited the aforementioned interactions abolishing altered microvilli. This suggests that the interplay of prominin‐1‐ganglioside membrane complexes, phosphoinositide 3‐kinase and cytoskeleton components regulates microvillar architecture. Lastly, the expression of prominin‐1 and its mutants modified the structure of filopodia emerging from fibroblast‐like cells and silencing human prominin‐1 in primary hematopoietic stem cells resulted in the loss of uropod‐associated microvilli. Altogether, these findings strengthen the role of prominin‐1 as an organizer of cellular protrusions.

PROM1 and PROM2 expression differentially modulates clinical prognosis of cancer: a multiomics analysis

“…Prominins have been shown to contribute to the generation and development of various cancers [4,6,86]. PROM1 is reported to be a regulator of stem cell activation by modifying microvillar architecture and dynamics and ciliary dynamics [12,18]. PROM2 can cause cellular protrusions and enhance phosphorylation of caveolin-1 to promote endocytosis [23].…”

“…PROM1 is commonly reported as a marker of neuronal and hematopoietic stem cells [4], but it is also expressed in CSCs and cancer cells, including in breast cancer [5], acute myeloid leukemia (AML) [10], and various pediatric brain tumors [11]. In addition, PROM1 is involved in maintaining microvillar architecture and dynamics [12]. Recent studies suggest that PROM1 is upregulated in non-small cell lung cancer tissue compared to normal lung tissue, and mutations in PROM1 are associated with poor prognosis [13,14].…”

Prominins control ciliary length throughout the animal kingdom: New lessons from human prominin-1 and zebrafish prominin-3

“…Mutations in the ganglioside binding site of PROM1 or variations in the level of membrane cholesterol influence its specific subcellular localization as well as the organization of membrane protrusions and/or the dynamics of the vesicles budding thereof (21,(26)(27)(28). The direct interaction of prom1 (or prom2) with cholesterol (21,26,29), and potentially other membrane lipids such as monosialotetrahexosylganglioside (GM1) (30,31), might account for these peculiarities.…”

“…For instance, the binding of prom1 to protocadherin 21 organizes the nascent precursor of photoreceptive membranes at the base of the outer segment (9). The interaction of prom1 with the actin-related protein (Arp) 2/3 complex, which mediates branching of actin networks, favors the formation of clusters of microvilli in epithelial cells and filopodia in non-epithelial cells (28). The latter observation might be associated with the implication of prom1 in cancer cell migration (32).…”

“…The selective binding of prom1 to ADPribosylation factor-like protein 13B (Arl13b) or histone deacetylase 6 (HDAC6) can orchestrate the functionality and dynamics of primary cilia, and consequently the activation of stem cells (33). The interactions of Prom1 with Arl13b/HDAC6 appear to be dependent on cytoplasmic lysine 138 (numbered according to prom1 splice variant s2) (33,34), while binding to Arp2/3 complex is stimulated by phosphorylation of a Cterminal tyrosine residue located at position 819/828 (s1/s2 variant) (28,35). This posttranslational modification also promotes the interaction of prom1 with the p85 subunit of phosphoinositide 3-kinase (PI3K) thereby activating the transformation of phosphatidylinositol(4,5)-bisphosphate (PIP2) into phosphatidylinositol(3,4,5)trisphosphate (PIP3) at the inner leaflet of the plasma membrane (36), which plays a pivotal role in the organization of plasma membrane protrusions (28).…”