Membrane and raft association of reggie-1/flotillin-2: role of myristoylation, palmitoylation and oligomerization and induction of filopodia by overexpression.
The reggie protein family consists of two proteins, reggie-1 and -2, also called flotillins, which are highly ubiquitous and evolutionarily conserved. Both reggies have been shown to be associated with membrane rafts and are involved in various cellular processes such as T-cell activation, phagocytosis and insulin signalling. However, the exact molecular function of these proteins remains to be determined. In addition, the mechanism of membrane association of reggie-1, which does not contain any transmembrane domain, is not known. In this study, we have produced a fusion protein of reggie-1 with enhanced green fluorescent protein and generated targeted substitutions for the inactivation of putative palmitoylation and myristoylation sites. We were able to show that reggie-1 is myristoylated and multiply palmitoylated and that lipid modifications are necessary for membrane association of reggie-1. Overexpression of reggie-1 resulted in the induction of numerous filopodia-like protrusions in various cell lines, suggesting a role for reggie-1 as a signalling protein in actin-dependent processes.
Institute of Biochemistry II, Medical School, University of Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
Carolin
C
Neumann-Giesen
Bianca
B
Falkenbach
Peter
P
Beicht
Stephanie
S
Claasen
Georg
G
Lüers
Claudia A O
CA
Stuermer
Volker
V
Herzog
Ritva
R
Tikkanen
D000215:Acylation; D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D004847:Epithelial Cells / Q000648:ultrastructure; D015870:Gene Expression; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009227:Myristic Acids / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019308:Palmitic Acid / Q000378:metabolism*; D011554:Pseudopodia / Q000648:ultrastructure*; D051381:Rats; D014162:Transfection
D008565:Membrane Proteins; D009227:Myristic Acids; D009419:Nerve Tissue Proteins; C106354:flotillins; D019308:Palmitic Acid