Discovery of new cargo proteins that enter cells through clathrin-independent endocytosis.
نویسندگان
چکیده
Clathrin-independent endocytosis (CIE) allows internalization of plasma membrane proteins lacking clathrin-targeting sequences, such as the major histocompatibility complex class I protein (MHCI), into cells. After internalization, vesicles containing MHCI fuse with transferrin-containing endosomes generated from clathrin-dependent endocytosis. In HeLa cells, MHCI is subsequently routed to late endosomes or recycled back out to the plasma membrane (PM) in distinctive tubular carriers. Arf6 is associated with endosomal membranes carrying CIE cargo and expression of an active form of Arf6 leads to the generation of vacuolar structures that trap CIE cargo immediately after endocytosis, blocking the convergence with transferrin-containing endosomes. We isolated these trapped vacuolar structures and analyzed their protein composition by mass spectrometry. Here we identify and validate six new endogenous cargo proteins (CD44, CD55, CD98, CD147, Glut1, and ICAM1) that use CIE to enter cells. CD55 and Glut1 appear to closely parallel the trafficking of MHCI, merging with transferrin endosomes before entering the recycling tubules. In contrast, CD44, CD98, and CD147 appear to directly enter the recycling tubules and by-pass the merge with EEA1-positive, transferrin-containing endosomes. This divergent itinerary suggests that sorting may occur along this CIE pathway. Furthermore, the identification of new cargo proteins will assist others studying CIE in different cell types and tissues.
منابع مشابه
TRE 17 / USP 6 regulates ubiquitination and trafficking of cargo proteins that enter cells by clathrin - independent endocytosis
متن کامل
TRE17/USP6 regulates ubiquitylation and trafficking of cargo proteins that enter cells by clathrin-independent endocytosis.
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Following endocytosis, internalized plasma membrane proteins can be recycled back to the cell surface or trafficked to late endosomes/lysosomes for degradation. Here we report on the trafficking of multiple proteins that enter cells by clathrin-independent endocytosis (CIE) and determine that a set of proteins (CD44, CD98, and CD147) found primarily in recycling tubules largely failed to reach ...
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Many plasma membrane (PM) proteins enter cells nonselectively through clathrin-independent endocytosis (CIE). Here, we present evidence that cytoplasmic sequences in three CIE cargo proteins-CD44, CD98, and CD147-were responsible for the rapid sorting of these proteins into endosomal tubules away from endosomes associated with early endosomal antigen 1 (EEA1). We found that Hook1, a microtubule...
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ورودعنوان ژورنال:
- Traffic
دوره 10 5 شماره
صفحات -
تاریخ انتشار 2009