Palmitoylation of tetraspanin proteins: modulation of CD151 lateral interactions, subcellular distribution, and integrin-dependent cell morphology.
Here we demonstrate that multiple tetraspanin (transmembrane 4 superfamily) proteins are palmitoylated, in either the Golgi or a post-Golgi compartment. Using CD151 as a model tetraspanin, we identified and mutated intracellular N-terminal and C-terminal cysteine palmitoylation sites. Simultaneous mutations of C11, C15, C242, and C243 (each to serine) eliminated >90% of CD151 palmitoylation. Notably, palmitoylation had minimal influence on the density of tetraspanin protein complexes, did not promote tetraspanin localization into detergent-resistant microdomains, and was not required for CD151-alpha 3 beta 1 integrin association. However, the CD151 tetra mutant showed markedly diminished associations with other cell surface proteins, including other transmembrane 4 superfamily proteins (CD9, CD63). Thus, palmitoylation may be critical for assembly of the large network of cell surface tetraspanin-protein interactions, sometimes called the "tetraspanin web." Also, compared with wild-type CD151, the tetra mutant was much more diffusely distributed and showed markedly diminished stability during biosynthesis. Finally, expression of the tetra-CD151 mutant profoundly altered alpha 3 integrin-deficient kidney epithelial cells, such that they converted from a dispersed, elongated morphology to an epithelium-like cobblestone clustering. These results point to novel biochemical and biological functions for tetraspanin palmitoylation.
Yang
Xiuwei
X
Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Claas
Christoph
C
Kraeft
Stine-Kathrein
SK
Chen
Lan Bo
LB
Wang
Zemin
Z
Kreidberg
Jordan A
JA
Hemler
Martin E
ME
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D048429:Cell Size; D049452:Green Fluorescent Proteins; D006801:Humans; D007202:Indicators and Reagents / Q000378:metabolism; D039201:Integrin alpha3beta1 / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010168:Palmitates / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D060185:Tetraspanin 24
D015703:Antigens, CD; C554715:CD151 protein, human; D007202:Indicators and Reagents; D039201:Integrin alpha3beta1; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010168:Palmitates; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D060185:Tetraspanin 24; D049452:Green Fluorescent Proteins; D020126:Brefeldin A