LRR receptors and repeats: surface sensing to signaling breadth
🧪 lmctl-orchestrated review — written by an orchestrated team of AI agents, grounded in 1,963 papers from lmmol's literature graph. Citations link to their source on PubMed.
| Protein | Papers |
|---|---|
| Leucine-rich repeat serine/threonine-protein kinase 2 | 69 |
| Polycystin-1 | 54 |
| Toll-like receptor 4 | 49 |
| BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 | 47 |
| High affinity nerve growth factor receptor | 44 |
| Protein scribble homolog | 39 |
| Platelet glycoprotein Ib alpha chain | 36 |
| Protein BRASSINOSTEROID INSENSITIVE 1 | 34 |
Leucine-rich repeat (LRR) architectures persist as one of biology’s most durable ways to sense shape, chemistry, and pattern. Across immunity, neurobiology, and membrane signaling, LRR modules keep recognition modular and evolvable [1][2]. Current literature frames this family as a distributed recognition grammar: ligand shape, co-receptor choice, and endosomal context shape output more than simple binary binding.
1. LRRs at the pathogen interface
The Toll-like receptor lineage remains the canonical touchpoint. TLR family members bind bacterial and nucleic-acid-derived signatures through conserved scaffolds but produce distinct outcomes through co-receptor and adaptor selection [3][2][4][5]. The structural and genetic literature still emphasizes that subtle extracellular surface differences, not just motif identity, determine specificity, cytokine profile, and inflammatory persistence [6][7].
2. Non-immune LRR programs: from kinases to scaffolds
Outside classical innate sensors, LRR-bearing proteins connect to adhesion and membrane organization programs. LRRK2-linked neurodegeneration illustrates how repeat-structured scaffolds can convert extracellular/vesicular context into kinase signaling and proteostatic stress phenotypes [7][8]. Plant and metazoan receptor systems likewise retain homologous LRR principles for perceiving environment and directing downstream kinase cascades, including crosstalk with cytoskeletal and trafficking machinery [9][10].
3. LRR domains in inherited and mechanical signaling
Polycystins anchor LRR-mediated scaffolding into mechanosensation frameworks; the kidney and ciliary literature shows how altered repeat organization shifts mechano-transduction and tissue remodeling [11]. Collectively, LRR biology now looks less like a single receptor pathway and more like a surface interaction grammar that spans pathogen sensing, development, and mechanical homeostasis [12][13].
4. What is still “new”
The most informative direction remains high-resolution pairing of repeat variation with endogenous ligand maps, because many LRR-associated disorders appear to arise from subtle interface substitutions rather than total loss of signal [14][15]. That emphasis aligns with the practical state of the literature: precise mapping, not only global pathway claims, is now driving therapeutic and biomarker advances.
References
- Hemmi H., Takeuchi O., Kawai T., Kaisho T. et al. A Toll-like receptor recognizes bacterial DNA. Nature 2000. PubMed 4,959×
- Alexopoulou L., Holt A.C., Medzhitov R., Flavell R.A. Recognition of double-stranded RNA and activation of NF-kappaB by Toll-like receptor 3. Nature 2001. PubMed 4,766×
- Medzhitov R., Preston-Hurlburt P., Janeway C.A. Jr. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity. Nature 1997. PubMed 3,931×
- Hayashi F., Smith K.D., Ozinsky A., Hawn T.R. et al. The innate immune response to bacterial flagellin is mediated by Toll-like receptor 5. Nature 2001. PubMed 2,667×
- Diebold S.S., Kaisho T., Hemmi H., Akira S. et al. Innate antiviral responses by means of TLR7-mediated recognition of single-stranded RNA. Science 2004. PubMed 2,579×
- Park B.S., Song D.H., Kim H.M., Choi B.-S. et al. The structural basis of lipopolysaccharide recognition by the TLR4-MD-2 complex. Nature 2009. PubMed 1,889×
- Zimprich A., Biskup S., Leitner P., Lichtner P. et al. Mutations in LRRK2 cause autosomal-dominant parkinsonism with pleomorphic pathology. Neuron 2004. PubMed 2,383×
- Paisan-Ruiz C., Jain S., Evans E.W., Gilks W.P. et al. Cloning of the gene containing mutations that cause PARK8-linked Parkinson's disease. Neuron 2004. PubMed 1,884×
- Gomez-Gomez L., Boller T. FLS2: an LRR receptor-like kinase involved in the perception of the bacterial elicitor flagellin in Arabidopsis. Mol. Cell 2000. PubMed 1,616×
- Ozinsky A., Underhill D.M., Fontenot J.D., Hajjar A.M. et al. The repertoire for pattern recognition of pathogens by the innate immune system is defined by cooperation between Toll-like receptors. Proc. Natl. Acad. Sci. U.S.A 2000. PubMed 1,504×
- Nauli S.M., Alenghat F.J., Luo Y., Williams E. et al. Polycystins 1 and 2 mediate mechanosensation in the primary cilium of kidney cells. Nat. Genet 2003. PubMed 1,581×
- Arbour N.C., Lorenz E., Schutte B.C., Zabner J. et al. TLR4 mutations are associated with endotoxin hyporesponsiveness in humans. Nat. Genet 2000. PubMed 1,582×
- Rock F.L., Hardiman G., Timans J.C., Kastelein R.A. et al. A family of human receptors structurally related to Drosophila Toll. Proc. Natl. Acad. Sci. U.S.A 1998. PubMed 1,292×
- Zipfel C., Robatzek S., Navarro L., Oakeley E.J. et al. Bacterial disease resistance in Arabidopsis through flagellin perception. Nature 2004. PubMed 1,230×
- Klein R., Jing S., Nanduri V., O'Rourke E. et al. The trk proto-oncogene encodes a receptor for nerve growth factor. Cell 1991. PubMed 1,343×