PDBsum entry 1v49

Structural protein

PDB id: 1v49

Contents

Protein chain

120 a.a. *

* Residue conservation analysis

PDB id:

1v49

Name:

Structural protein

Title:

Solution structure of microtubule-associated protein light chain-3

Structure:

Microtubule-associated proteins 1a/1b light chain 3b. Chain: a. Fragment: residues 1-120. Synonym: microtubule-associated protein light chain-3. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

1 models

Authors:

T.Kouno,M.Mizuguchi,I.Tanida,T.Ueno,E.Kominami,K.Kawano

Key ref:

T.Kouno et al. (2005). Solution structure of microtubule-associated protein light chain 3 and identification of its functional subdomains. J Biol Chem, 280, 24610-24617. PubMed id: 15857831 DOI: 10.1074/jbc.M413565200

Date:

11-Nov-03 Release date: 28-Dec-04

Protein chain

Q9GZQ8  (MLP3B_HUMAN) -  Microtubule-associated proteins 1A/1B light chain 3B from Homo sapiens

Seq: 125 a.a.

Struc: 120 a.a.

DOI no: 10.1074/jbc.M413565200

J Biol Chem 280:24610-24617 (2005)

PubMed id: 15857831

Solution structure of microtubule-associated protein light chain 3 and identification of its functional subdomains.

T.Kouno, M.Mizuguchi, I.Tanida, T.Ueno, T.Kanematsu, Y.Mori, H.Shinoda, M.Hirata, E.Kominami, K.Kawano.

ABSTRACT

Microtubule-associated protein (MAP) light chain 3 (LC3) is a human homologue of yeast Apg8/Aut7/Cvt5 (Atg8), which is essential for autophagy. MAP-LC3 is cleaved by a cysteine protease to produce LC3-I, which is located in cytosolic fraction. LC3-I, in turn, is converted to LC3-II through the actions of E1- and E2-like enzymes. LC3-II is covalently attached to phosphatidylethanolamine on its C terminus, and it binds tightly to autophagosome membranes. We determined the solution structure of LC3-I and found that it is divided into N- and C-terminal subdomains. Additional analysis using a photochemically induced dynamic nuclear polarization technique also showed that the N-terminal subdomain of LC3-I makes contact with the surface of the C-terminal subdomain and that LC3-I adopts a single compact conformation in solution. Moreover, the addition of dodecylphosphocholine into the LC3-I solution induced chemical shift perturbations primarily in the C-terminal subdomain, which implies that the two subdomains have different sensitivities to dodecylphosphocholine micelles. On the other hand, deletion of the N-terminal subdomain abolished binding of tubulin and microtubules. Thus, we showed that two subdomains of the LC3-I structure have distinct functions, suggesting that MAP-LC3 can act as an adaptor protein between microtubules and autophagosomes.

Selected figure(s)

Figure 1.
FIG. 1. Solution structure of the unmodified form of MAP-LC3 (LC3-I). A, stereo view of the backbone heavy atom (N, C , and C') traces of 15 superimposed structures of LC3-I obtained from the structure calculations. The N-terminal (residues 1 to 29) and C-terminal (residues 30 to 120) subdomains are shown in green and blue, respectively. B, ribbon presentation of the energy-minimized average structure of LC3-I. The representation is oriented as in panel A. All tyrosine (Tyr-38, Tyr-99, Tyr-110, and Tyr-113) and histidine (His-27, His-57, and His-86) residues in LC3-I are shown as ball-and-stick representations. Residues Ile-34, Ile-35, and Ile-67 include ^1H resonances showing the upfield shift.

Figure 4.
FIG. 4. Binding assays of wild-type LC3-I and the mutant, LC3-I N. A, surface plasmon resonance study of tubulin binding by LC3-I. For both LC3-I (left) and LC3-I N (right), samples of various concentrations (2.5, 5.0, 7.5, and 10 µM) were injected over immobilized tubulin. The inset shows the sensorgrams when 400 mM NaCl was injected into the flow cells. B, co-sedimentation assay of LC3-I and LC3-I N with tubulin-polymerized microtubules. Wild-type LC3-I (lane 1) or LC3-I N(lane 2) proteins were incubated with microtubules and subjected to centrifugation. Sedimented proteins were analyzed by SDS-PAGE. As a control, a binding assay between LC3-I and microtubules was performed in the presence of 400 mM NaCl (lane 3). Positions of bands for tubulin, LC3-I, and LC3-I N are indicated by arrowheads.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 24610-24617) copyright 2005.

Figures were selected by an automated process.