Caenorhabditiseleganschaperonin CCT/TRiC is required for actin and tubulin biogenesis and microvillus formation in intestinal epithelial cells

Abstract

Caenorhabditis elegans chaperonin CCT is required for the biogenesis of actin and tubulin and is thereby essential for microvillus formation in intestinal cells. Loss of CCT/TRiC had no strong effects on intermediate filament protein IFB-2 or cytoskeletal linker protein ERM-1, suggesting that CCT/TRiC exhibits clear substrate specificity in living animals.

Noncentrosomal microtubules in C. elegans epithelia

“…One paper has addressed the role of the cytosolic CCT/TRiC chaperonin in the intestine (Saegusa et al, 2014); other chaperonins of the CCT and prefoldin families have been showed to affect MTs in the epidermis (Quintin et al, 2016).…”

“…The establishment and maintenance of polarity is highly dependent on protein recycling at the plasma membrane (Shivas et al, 2010). Protein recycling is a two-step process whereby proteins are first subjected to internalization through clathrin-dependent endocytosis or clathrin-independent endocytosis (Goldenring, 2015;Sato et al, 2014). Once internalized, these endocytic vesicles are delivered to peripheral organelles known as sorting endosomes, also called early endosomes.…”

“…Once internalized, these endocytic vesicles are delivered to peripheral organelles known as sorting endosomes, also called early endosomes. From sorting endosomes, proteins can undergo either degradation when sorted to late endosomes or recycling to the plasma membrane (Grant and Donaldson, 2009;Sato et al, 2014). Indeed, sorting endosomes are tubulovesicular structures from which proteins can return to the cell surface by a fast recycling process involving RAB4.…”

“…Studies relying on C. elegans intestinal cells have long contributed to our understanding of trafficking in epithelia, because their large size (15 mm in the apicobasal axis) offers a good resolution for live microscopy (Grant and Donaldson, 2009;Sato et al, 2014). A recent study based on the expression of two human proteins known to be recycled, the transferrin receptor and the alpha-chain of the IL-2 receptor, has shown that endocytic tubules emerge from basal sorting endosomes to allow basolateral recycling in adult intestinal cells (Fig.…”

“…Second, the AP-1 clathrin adaptor (known as APS-1 in C. elegans) is required for actin organization and apical targeting of several proteins including the polarity factor PAR-6 and E-cadherin (Gillard et al, 2015;Shafaq-Zadah et al, 2012;Zhang et al, 2012). Third, loss of APS-1 induces ectopic mini-intestinal lumen also observed after the loss of the cytosolic chaperonin CCT-1 (also known as TCP-1), which affects both the actin and MT filaments (Saegusa et al, 2014;Shafaq-Zadah et al, 2012;Zhang et al, 2012).…”