title: The ubiquitin-like protein PLIC-2 is a negative regulator of G protein-coupled receptor endocytosis.
abstract: The activity of many signaling receptors is regulated by their endocytosis via clathrin-coated pits (CCPs). For G protein-coupled receptors (GPCRs), recruitment of the adaptor protein arrestin to activated receptors is thought to be sufficient to drive GPCR clustering in CCPs and subsequent endocytosis. We have identified an unprecedented role for the ubiquitin-like protein PLIC-2 as a negative regulator of GPCR endocytosis. Protein Linking IAP to Cytoskeleton (PLIC)-2 overexpression delayed ligand-induced endocytosis of two GPCRs: the V2 vasopressin receptor and beta-2 adrenergic receptor, without affecting endocytosis of the transferrin or epidermal growth factor receptor. The closely related isoform PLIC-1 did not affect receptor endocytosis. PLIC-2 specifically inhibited GPCR concentration in CCPs, without affecting membrane recruitment of arrestin-3 to activated receptors or its cellular levels. Depletion of cellular PLIC-2 accelerated GPCR endocytosis, confirming its regulatory function at endogenous levels. The ubiquitin-like domain of PLIC-2, a ligand for ubiquitin-interacting motifs (UIMs), was required for endocytic inhibition. Interestingly, the UIM-containing endocytic adaptors epidermal growth factor receptor protein substrate 15 and Epsin exhibited preferential binding to PLIC-2 over PLIC-1. This differential interaction may underlie PLIC-2 specific effect on GPCR endocytosis. Identification of a negative regulator of GPCR clustering reveals a new function of ubiquitin-like proteins and highlights a cellular requirement for exquisite regulation of receptor dynamics.
authors.affiliation: Macrophage Biology Laboratory, Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
authors.forename: Elsa-Noah
authors.initials: EN
authors.lastname: N'Diaye
authors.forename: Aylin C
authors.initials: AC
authors.lastname: Hanyaloglu
authors.forename: Kimberly K
authors.initials: KK
authors.lastname: Kajihara
authors.forename: Manojkumar A
authors.initials: MA
authors.lastname: Puthenveedu
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Mark
authors.initials: M
authors.lastname: von Zastrow
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Brown
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D020816:Amino Acid Motifs; D019390:Arrestins / Q000378:metabolism; D000071183:Autophagy-Related Proteins; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D022163:Clathrin-Coated Vesicles / Q000378:metabolism; D004705:Endocytosis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D017483:Receptors, Vasopressin / Q000378:metabolism*; D014452:Ubiquitins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D019390:Arrestins; D000071183:Autophagy-Related Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C486206:EPS15 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D018343:Receptors, Adrenergic, beta-2; D017483:Receptors, Vasopressin; C107792:UBQLN1 protein, human; C405662:UBQLN2 protein, human; D014452:Ubiquitins; C082333:arrestin3; C114154:epsin