Transmembrane domains control exclusion of membrane proteins from clathrin-coated pits

Abstract

SummaryEfficient sorting of proteins is essential to allow transport between intracellular compartments while maintaining their specific composition. During endocytosis, membrane proteins can be concentrated in endocytic vesicles by specific interactions between their cytoplasmic domains and cytosolic coat proteins. It is, however, unclear whether they can be excluded from transport vesicles and what the determinants for this sorting could be. Here, we show that in the absence of cytosolic sorting signals, transmembrane domains control the access of surface proteins to endosomal compartments. They act in particular by determining the degree of exclusion of membrane proteins from endocytic clathrin-coated vesicles. When cytosolic endocytosis signals are present, it is the combination of cytosolic and transmembrane determinants that ultimately controls the efficiency with which a given transmembrane protein is endocytosed.

A Systematic Approach to Pair Secretory Cargo Receptors with Their Cargo Suggests a Mechanism for Cargo Selection by Erv14

“…These puncta co-localized with the late Golgi marker Sec7, but not with the early Golgi marker Rud3, confirming that the protein was accumulating in trans Golgi compartments (Figure 6B and 6C). The same Golgi accumulation of shorter TMDs was observed in cells lacking the End3 protein that is required for endocytosis [40], negating the possibility that the shorter TMD variants are simply travelling to the surface and being more rapidly endocytosed (Figure 6D) [41].…”

TM9/Phg1 and SadA proteins control surface expression and stability of SibA adhesion molecules inDictyostelium

“…The PCR fragment was digested with Hpa I and Kpn I and cloned into prepSC3 (a pDXA-3C plasmid with a modified Hin dIII- Hpa I- Kpn I- Not I- Xba I multiple-cloning site [ Manstein et al , 1995]) digested with Hpa I- Kpn I, creating the csA-0 intermediate construct. The csA-TM construct was obtained by amplifying the sequence coding for the transmembrane domain of CD1b-TM3 (21 aa; Mercanti et al , 2010) and subcloning it in csA-0, using the Kpn I and Xba I sites. The amino acid sequence of the transmembrane domain of csA-TM is: ESD SIVLAIIVPSLLLLLCLALLW YMRRRSM.…”

Golgi-Dependent Transport of Vacuolar Sorting Receptors Is Regulated by COPII, AP1, and AP4 Protein Complexes in Tobacco

“…In mammalian cells, it has been suggested that exclusion of membrane proteins with long transmembrane domains from clathrin-coated pits explains higher steady state levels at the PM (Mercanti et al, 2010). If the rate of exocytosis is unaffected, it would explain why the proteins yield a higher steady state level at the PM without mediating a more pronounced drag-and-drop missorting of vacuolar cargo.…”