Implications of the differing roles of the β1 and β3 transmembrane and cytoplasmic domains for integrin function

Lu, Zhenwei; Mathew, Sijo; Jiang, Chen; Hadziselimovic, Arina; Palamuttam, Riya J.; Hudson, Billy G.; Fässler, Reinhard; Pozzi, Ambra; Sanders, Charles R.; Zent, Roy

doi:10.7554/elife.18633

Cited by 34 publications

(42 citation statements)

References 65 publications

(109 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The homology model began with the entire cytoplasmic domains of both αv and β3 as α-helical, yet we observed that only αv V993-V1024 and β3 D718-N769 had persistent α-helical structure with the remaining regions in extended conformations. This is consistent with NMR measurements of a β3 TM-cytoplasmic construct in DHPC:DMPC bicelles where β3 was helical through residue A737, well beyond the TM domain and into the cytoplasm (24). Also consistent with this NMR study, K713 (numbered K716 in ref.…”

Section: Discussionsupporting

confidence: 89%

“…Our MD simulations are also consistent with numerous experimentally reported features of the αvβ3 cytosolic and juxtamembrane regions (24,36). The homology model began with the entire cytoplasmic domains of both αv and β3 as α-helical, yet we observed that only αv V993-V1024 and β3 D718-N769 had persistent α-helical structure with the remaining regions in extended conformations.…”

Section: Discussionsupporting

confidence: 89%

“…Thus, the geometry of the isolated αvβ3 TM domain heterodimer assembled in bacterial membranes appears to differ from the geometry of the TM domain heterodimer when it is present in the context of the full-length receptor and expressed in mammalian membranes. This suggests that either the lipid environment or contiguous extracellular or intracellular sequences influence the conformation of the αv TM domain (24,25).…”

Section: Discussionmentioning

confidence: 99%

“…Also consistent with this NMR study, K713 (numbered K716 in ref. 24) snorkeled its amine moiety to the cytoplasmic lipid head-group region in the majority of simulations. We also found that the R995-to-E723 salt bridge previously suggested to stabilize the low-affinity state of αvβ3 (36) formed during the initial structural relaxation of the αvβ3 homology model and was maintained through the first 260 ns of simulation, even during the TM helix dissociation event (SI Appendix, Fig.…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Unique transmembrane domain interactions differentially modulate integrin αvβ3 and αIIbβ3 function

Litvinov

Mravic

Zhu

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Lateral transmembrane (TM) helix–helix interactions between single-span membrane proteins play an important role in the assembly and signaling of many cell-surface receptors. Often, these helices contain two highly conserved yet distinct interaction motifs, arranged such that the motifs cannot be engaged simultaneously. However, there is sparse experimental evidence that dual-engagement mechanisms play a role in biological signaling. Here, we investigate the function of the two conserved interaction motifs in the TM domain of the integrin β3-subunit. The first motif uses reciprocating “large-large-small” amino acid packing to mediate the interaction of the β3 and αIIb TM domains and maintain the inactive resting conformation of the platelet integrin αIIbβ3. The second motif, S-x3-A-x3-I, is a variant of the classical “G-x3-G” motif. Using site-directed mutagenesis, optical trap-based force spectroscopy, and molecular modeling, we show that S-x3-A-x3-I does not engage αIIb but rather mediates the interaction of the β3 TM domain with the TM domain of the αv-subunit of the integrin αvβ3. Like αIIbβ3, αvβ3 on circulating platelets is inactive, and in the absence of platelet stimulation is unable to interact with components of the subendothelial matrix. However, disrupting any residue in the β3 S-x3-A-x3-I motif by site-directed mutations is sufficient to induce αvβ3 binding to the αvβ3 ligand osteopontin and to the monoclonal antibody WOW-1. Thus, the β3-integrin TM domain is able to engage in two mutually exclusive interactions that produce alternate α-subunit pairing, creating two integrins with distinct biological functions.

show abstract

Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Unique transmembrane domain interactions differentially modulate integrin αvβ3 and αIIbβ3 function

Litvinov

Mravic

Zhu

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Among 24 different integrin isoforms, the α ν β 3 and α 5 β 1 integrins, have important, but potentially separate roles in the assembly of adhesions and the physiology of many cell types [21,23,32–34,24–31]. Nanoscale differences in physical properties between α ν β 3 and α 5 β 1 integrins can determine how nascent adhesions assemble [35], their organization [36–38], transmitted traction [30,39] and lifetime [40], on account of their different properties. For example, it has been reported that the rate of integrin activation, k a , determines the number of integrins per adhesion [22,41], while lateral clustering, or avidity, E II , increases the size of individual adhesions [22,42–44].…”

Section: Introductionmentioning

confidence: 99%

Multiscale model of integrin adhesion assembly

Bidone

Skeeters

Oakes

et al. 2019

Preprint

View full text Add to dashboard Cite

36The ability of adherent cells to form adhesions is critical to several phases of their physiology. The 37 assembly of adhesions is mediated by several types of integrins. These integrins differ in physical 38 properties, including rate of diffusion on the plasma membrane, rapidity of changing conformation 39 from bent to extended, affinity for extracellular matrix ligands, and lifetimes of their ligand-bound 40 states. However, the way in which nanoscale physical properties of integrins ensure proper 41 adhesion assembly remains elusive. We observe experimentally that both b-1 and b-3 integrins 42 localize in nascent adhesions at the cell leading edge. In order to understand how different 43 nanoscale parameters of b-1 and b-3 integrins mediate proper adhesion assembly, we therefore 44 develop a coarse-grained computational model. Results from the model demonstrate that 45 morphology and distribution of nascent adhesions depend on ligand binding affinity and strength 46 of pairwise interactions. Organization of nascent adhesions depends on the relative amounts of 47 integrins with different bond kinetics. Moreover, the model shows that the architecture of an actin 48 filament network does not perturb the total amount of integrin clustering and ligand binding; 49 however, only bundled actin architectures favor adhesion stability and ultimately maturation.50Together, our results support the view that cells can finely tune the expression of different integrin 51 types to determine both structural and dynamic properties of adhesions. 52 53 3 Author summary 54 Integrin-mediated cell adhesions to the extracellular environment contribute to various cell 55 activities and provide cells with vital environmental cues. Cell adhesions are complex structures 56 that emerge from a number of molecular and macromolecular interactions between integrins and 57 cytoplasmic proteins, between integrins and extracellular ligands, and between integrins 58 themselves. How the combination of these interactions regulate adhesions formation remains 59 poorly understood because of limitations in experimental approaches and numerical methods.60 Here, we develop a multiscale model of adhesion assembly that treats individual integrins and 61 elements from both the cytoplasm and the extracellular environment as single coarse-grained (CG) 62 point particles, thus simplifying the description of the main macromolecular components of 63 adhesions. The CG model implements sequential interactions and dependencies between the 64 components and ultimately allows one to characterize various regimes of adhesions formation 65 based on experimentally detected parameters. The results reconcile a number of independent 66 experimental observations and provide important insights into the molecular basis of adhesion 67 assembly from various integrin types. 68 69 As the linker between cytoskeletal adhesion proteins and extracellular matrix ligands, integrins 70 play a vital role in the formation of adhesions and profoundly influence different phases of cell...

show abstract

Frontline Science: A flexible kink in the transmembrane domain impairs β2 integrin extension and cell arrest from rolling

Sun

Fan

Gingras

et al. 2019

Journal of Leukocyte Biology

View full text Add to dashboard Cite

β2 integrins are the main adhesion molecules in neutrophils and other leukocytes and are rapidly activated by inside-out signaling, which results in conformational changes that are transmitted through the transmembrane domain (TMD). Here, we investigated the biologic effect of introducing a proline mutation in the β2 integrin TMD to create a flexible kink that uncouples the topology of the inner half of the TMD from the outer half and impairs integrin activation. The β2 integrin alpha chains, αL, αM, αX, and αD, all contain an inserted (I) domain with homology to von Willebrand factor A domain. β2 activation was monitored in a homogenous binding assay of 2 reporter monoclonal antibodies: KIM127 reporting extension (E +) and mAb24 reporting the highaffinity (H +) conformation of the β2 I-like domain. The proline mutation partially diminished chemokine-induced extension, but not the high-affinity conformation. The proline mutation in the TMD of β2 completely inhibited arrest of rolling HL-60 cells in response to the chemokine IL-8. TMD mutant HL-60 cells rolling on P-selectin and ICAM-1 were unable to reduce their rolling velocity in response to IL-8. Quantitative dynamic footprinting live-cell imaging showed that blocking TMD topology transmission impaired the chemokine-induced activation of β2, limiting the appearance of extended high-affinity (E + H +) β2. This also resulted in a defect in early spreading (3 min after arrest), which could be overcome by forced integrin activation using Mn 2+. We conclude that the TMD proline mutation severely impairs β2 integrin extension, cell arrest, and early spreading.

show abstract

Implications of the differing roles of the β1 and β3 transmembrane and cytoplasmic domains for integrin function

Cited by 34 publications

References 65 publications

Unique transmembrane domain interactions differentially modulate integrin αvβ3 and αIIbβ3 function

Unique transmembrane domain interactions differentially modulate integrin αvβ3 and αIIbβ3 function

Multiscale model of integrin adhesion assembly

Frontline Science: A flexible kink in the transmembrane domain impairs β2 integrin extension and cell arrest from rolling

Contact Info

Product

Resources

About