Abstract
The biogenesis of endothelial-specific Weibel-Palade bodies (WPB) is poorly understood, despite their key role in both haemostasis and inflammation. Biogenesis of specialized organelles of haemopoietic cells is often adaptor protein complex 3-dependent (AP-3-dependent), and AP-3 has previously been shown to play a role in the trafficking of both WPB membrane proteins, P-selectin and CD63. However, WPB are thought to form at the trans Golgi network (TGN), which is inconsistent with a role for AP-3, which operates in post-Golgi trafficking. We have therefore investigated in detail the mechanisms of delivery of these two membrane proteins to WPB. We find that P-selectin is recruited to forming WPB in the trans-Golgi by AP-3-independent mechanisms that use sorting information within both the cytoplasmic tail and the lumenal domain of the receptor. In contrast, CD63 is recruited to already-budded WPB by an AP-3-dependent route. These different mechanisms of recruitment lead to the presence of distinct immature and mature populations of WPB in human umbilical vein endothelial cells (HUVEC).
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Adaptor Protein Complex 3
-
Amino Acid Sequence
-
Animals
-
Antigens, CD / metabolism*
-
Base Sequence
-
Cells, Cultured
-
DNA-Binding Proteins / metabolism
-
Endothelium, Vascular / metabolism
-
Endothelium, Vascular / ultrastructure
-
Humans
-
Leukocyte Rolling / physiology
-
Mice
-
Mice, Inbred C57BL
-
Mice, Mutant Strains
-
Microscopy, Electron
-
Models, Biological
-
P-Selectin / chemistry
-
P-Selectin / genetics
-
P-Selectin / metabolism*
-
Platelet Membrane Glycoproteins / metabolism*
-
Protein Sorting Signals / genetics
-
Protein Structure, Tertiary
-
Protein Transport
-
RNA, Small Interfering / genetics
-
Recombinant Fusion Proteins / chemistry
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / metabolism
-
Tetraspanin 30
-
Transcription Factors / metabolism
-
Weibel-Palade Bodies / metabolism*
-
Weibel-Palade Bodies / ultrastructure
-
trans-Golgi Network / metabolism
Substances
-
Adaptor Protein Complex 3
-
Antigens, CD
-
CD63 protein, human
-
Cd63 protein, mouse
-
DNA-Binding Proteins
-
P-Selectin
-
Platelet Membrane Glycoproteins
-
Protein Sorting Signals
-
RNA, Small Interfering
-
Recombinant Fusion Proteins
-
Tetraspanin 30
-
Transcription Factors