Amot recognizes a juxtanuclear endocytic recycling compartment via a novel lipid binding domain.
Polarity proteins promote the asymmetric organization of cells by orienting intracellular sorting mechanisms, such as protein trafficking and cytoskeletal assembly. The localization of individual polarity proteins in turn is often determined by association with factors that mediate contact with other cells or the substratum. This arrangement for the Par and Crb apical polarity complexes at the tight junction is disrupted by the adaptor protein Amot. Amot directly binds the scaffolding proteins Patj and Mupp1 and redistributes them and their binding partners from the plasma membrane to endosomes. However, the mechanism by which Amot is targeted to endosomes is unknown. Here, a novel lipid binding domain within Amot is shown to selectively bind with high affinity to membranes containing monophosphorylated phosphatidylinositols and cholesterol. With similar lipid specificity, Amot inserts into and tubulates membranes in vitro and enlarges perinuclear endosomal compartments in cells. Based on the similar distribution of Amot with cholesterol, Rab11, and Arf6, such membrane interactions are identified at juxtanuclear endocytic recycling compartments. Taken together, these findings indicate that Amot is targeted along with associated apical polarity proteins to the endocytic recycling compartment via this novel membrane binding domain.
Heller
Brigitte
B
Department of Biochemistry and Molecular Biology, University of Indiana School ofMedicine, Indianapolis, Indiana 46202, USA.
Adu-Gyamfi
Emmanuel
E
Smith-Kinnaman
Whitney
W
Babbey
Cliff
C
Vora
Mohsin
M
Xue
Yi
Y
Bittman
Robert
R
Stahelin
Robert V
RV
Wells
Clark D
CD
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism; D000091082:Angiomotins; D000818:Animals; D001665:Binding Sites; D055592:Biophysical Phenomena; D002451:Cell Compartmentation; D002460:Cell Line; D016764:Cell Polarity / Q000502:physiology; D002784:Cholesterol / Q000378:metabolism; D004285:Dogs; D004705:Endocytosis / Q000502:physiology; D011992:Endosomes / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D008081:Liposomes; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors; D000091082:Angiomotins; D002784:Cholesterol; D036341:Intercellular Signaling Peptides and Proteins; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C423985:AMOT protein, human; C000715348:ARF6 protein, human