The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
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We are interested in where in or outside the cell the gene product carries out its function.
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Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Pelle (Pll) is a serine/threonine-protein kinase encoded by the pll gene (CG5974) in Drosophila melanogaster (towb2009tubeisan pages 5-6, schiffmann1999formationandbiochemical pages 2-3). The protein belongs to the interleukin-1 receptor-associated kinase (IRAK) family and is the functional homolog of mammalian IRAK proteins in the evolutionarily conserved Toll signaling pathway (towb2009tubeisan pages 10-11, gosu2012molecularevolutionand pages 11-12, gosu2012molecularevolutionand pages 4-5, gosu2012molecularevolutionand pages 1-2). Pelle is classified as a non-RD kinase, lacking the conserved arginine immediately preceding the catalytic aspartate residue that defines RD kinases (towb2009tubeisan pages 4-5).
Pelle is a 501-amino acid protein containing two principal structural domains (schiffmann1999formationandbiochemical pages 2-3). The N-terminal region (approximately residues 1-208, with a protease-resistant core spanning residues 24-140) comprises a death domain responsible for protein-protein interactions, particularly with the adaptor protein Tube (schiffmann1999formationandbiochemical pages 2-3, schiffmann1999formationandbiochemical pages 6-9). The C-terminal region (approximately residues 130-501) contains the catalytic serine/threonine kinase domain (towb2009tubeisan pages 5-6, daigneault2013theirakhomolog pages 3-5). This bipartite architecture separates the recruitment/regulatory function from the enzymatic activity, a characteristic feature of IRAK-family kinases (li2002irak4anovel pages 2-3).
Pelle functions as a serine/threonine-protein kinase that catalyzes the ATP-dependent phosphorylation of specific protein substrates (EC 2.7.11.1). The primary characterized reaction is the phosphorylation of Cactus, the Drosophila IκB homolog, at Toll-responsive serine residues (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 2-3).
Pelle exhibits preferential substrate specificity toward signal-dependent phosphorylation sites rather than acting as a general serine/threonine kinase. The best-characterized substrate is Cactus, where Pelle directly phosphorylates three key serine residues: Ser74, Ser78, and Ser116 (daigneault2013theirakhomolog pages 2-3). Mutation of these three sites reduces Pelle-mediated phosphorylation by approximately 75-80%, demonstrating their importance as primary Pelle targets (daigneault2013theirakhomolog pages 2-3). This substrate specificity is distinct from and reciprocal to that of Casein Kinase II (CKII): Pelle preferentially phosphorylates Toll-responsive sites, whereas CKII phosphorylates signal-independent PEST-domain sites in Cactus (daigneault2013theirakhomolog pages 2-3).
Pelle also phosphorylates the signal-responsive degron of mammalian IκBα at Ser32 and Ser36 when presented in a Cactus-IκBα chimera, demonstrating functional conservation with the mammalian IκB kinase (IKK) system despite Pelle being an IRAK-family member rather than an IKK (daigneault2013theirakhomolog pages 2-3). Additional Pelle substrates include dFoxO, which Pelle phosphorylates to regulate its subcellular localization and transcriptional activity (wu2015pellemodulatesdfoxomediated pages 2-3), and potentially Tube and Dorsal, though these remain less completely characterized (daigneault2013theirakhomolog pages 3-5).
| Substrate | Phosphorylation site(s) | Functional consequence of phosphorylation | Evidence and citations |
|---|---|---|---|
| Cactus (Drosophila IκB homolog) | Ser74, Ser78, Ser116 | Direct phosphorylation at Toll-responsive sites promotes recognition by Slimb/β-TrCP, ubiquitination, and proteasomal degradation of Cactus. This releases Dorsal or Dif for nuclear translocation and Toll-responsive transcription. Mutation of all three sites reduced Pelle-mediated phosphorylation by approximately 75–80%. | Direct biochemical and functional evidence (daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 1-2) |
| dFoxO | Not mapped | Pelle physically interacts with and directly phosphorylates dFoxO. The modification is proposed to favor cytoplasmic retention and suppress dFoxO-dependent transcription and apoptosis; loss of pll promotes dFoxO nuclear localization, Thor/4E-BP expression, caspase activation, and cell death. | Direct interaction and phosphorylation demonstrated; precise residues and recognition motif remain unknown (wu2015pellemodulatesdfoxomediated pages 2-3) |
| Tube (Toll-pathway adaptor) | Not mapped | Pelle phosphorylates Tube in vitro. This may alter Tube localization or stability and contribute to negative-feedback regulation or disassembly of the receptor-proximal Toll signaling complex, but the physiological sites and exact in-vivo consequence remain unresolved. | Biochemical evidence with a proposed feedback role (daigneault2013theirakhomolog pages 3-5, sun2004regulatedassemblyof pages 2-3) |
| Dorsal (NF-κB-family transcription factor) | Not mapped | Pelle interacts with Dorsal, and Dorsal phosphorylation has been proposed as an additional regulatory event. Direct physiological phosphorylation by Pelle and its functional consequence are not firmly established; the best-supported mechanism of Dorsal activation is indirect, through Cactus phosphorylation and degradation. | Candidate or speculative substrate, not equivalent in certainty to Cactus (daigneault2013theirakhomolog pages 1-2, govind1999controlofdevelopment pages 3-4, towb2009tubeisan pages 8-8, daigneault2013theirakhomolog pages 3-5) |
| Cactus–IκBα chimeric substrate | Mammalian IκBα-equivalent Ser32 and Ser36 in the signal-responsive degron | Pelle phosphorylates the canonical IκBα degron in the chimera, supporting functional similarity to mammalian IκB kinase despite Pelle being an IRAK-family kinase. The modification represents a degradation-associated phosphodegron. | Direct in-vitro evidence using a chimeric substrate; not evidence that native mammalian IκBα is a physiological Drosophila substrate (daigneault2013theirakhomolog pages 2-3) |
Table: Experimentally demonstrated and proposed Pelle substrates, their known phosphorylation sites, and downstream consequences. The table distinguishes well-supported physiological targets from candidate or artificial substrates.
Pelle is a cytoplasmic protein that carries out its enzymatic function at membrane-proximal signaling complexes (schirato2016toll2signallingsafeguards pages 20-24, daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 1-2, daigneault2013theirakhomolog pages 5-6). Before Toll activation, Pelle exists in the cytoplasm. Upon Toll receptor activation, Pelle is recruited to the plasma membrane through its association with the adaptor proteins MyD88 and Tube, forming a submembranous signaling complex (schirato2016toll2signallingsafeguards pages 20-24, chen2006weckleisa pages 2-3). This membrane-proximal localization is essential for efficient signal transduction. Pelle phosphorylates its primary substrate Cactus in the cytoplasm, promoting Cactus degradation and allowing the NF-κB-family transcription factor Dorsal to translocate to the nucleus (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 1-2, daigneault2013theirakhomolog pages 2-3).
Pelle functions as the central intracellular kinase in the Drosophila Toll pathway, mediating innate immune responses against fungi and Gram-positive bacteria (valanne2011thedrosophilatoll pages 4-5, daigneault2013theirakhomolog pages 1-2, daigneault2013theirakhomolog pages 2-3, schirato2016toll2signallingsafeguards pages 20-24). The canonical pathway architecture involves activation of Toll receptors by processed Spätzle ligand, recruitment of the death-domain adaptor MyD88, assembly of the MyD88-Tube-Pelle signaling complex, and Pelle-dependent phosphorylation of Cactus (sun2004regulatedassemblyof pages 1-2, daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 1-2). Phosphorylated Cactus is recognized by Slimb (the Drosophila β-TrCP homolog), leading to ubiquitination and proteasome-mediated degradation (daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 1-2). This releases the NF-κB-family transcription factors Dorsal and Dif, which translocate to the nucleus and activate antimicrobial peptide genes such as drosomycin (valanne2011thedrosophilatoll pages 4-5, daigneault2013theirakhomolog pages 2-3).
During embryogenesis, Pelle plays an essential role in establishing the dorsoventral axis through spatially regulated Toll signaling (sun2004regulatedassemblyof pages 1-2, govind1999controlofdevelopment pages 3-4, towb2009tubeisan pages 6-8). Maternal Toll activation on the ventral side of the embryo recruits the MyD88-Tube-Pelle complex, generating a graded nuclear Dorsal concentration from ventral to dorsal regions (sun2004regulatedassemblyof pages 1-2, sun2004regulatedassemblyof pages 2-3). This Dorsal gradient specifies mesodermal, neuroectodermal, lateral, and dorsal cell fates, with high ventral Dorsal concentrations inducing mesoderm formation and muscle development (wu2015pellemodulatesdfoxomediated pages 24-25, towb2009tubeisan pages 6-8).
Pelle participates in a highly regulated signaling complex organized through death-domain interactions (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 1-2, sun2004regulatedassemblyof pages 9-9). Before signaling, MyD88 and Tube form a preassembled complex localized to the plasma membrane (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 1-2, sun2004regulatedassemblyof pages 8-9). Upon Toll activation, this complex recruits Pelle through direct Tube-Pelle death-domain interactions (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 9-9, towb2009tubeisan pages 5-6). Tube functions as a bivalent adaptor, simultaneously binding MyD88 and Pelle through distinct surfaces on its death domain (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 9-9). Once assembled, Pelle undergoes activation through autophosphorylation, a process that does not require an upstream kinase (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 5-6). Pelle's kinase activity is not required for complex assembly, as catalytically inactive Pelle can still associate with MyD88 in a Tube-dependent manner (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 1-2). Activated Pelle may phosphorylate Tube, potentially providing negative feedback to regulate complex stability and signal duration (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 5-6, sun2004regulatedassemblyof pages 2-3).
Beyond canonical Toll signaling, Pelle regulates cell survival through a Toll-independent mechanism involving dFoxO phosphorylation (wu2015pellemodulatesdfoxomediated pages 2-3, wu2015pellemodulatesdfoxomediated pages 24-25). Loss of pll results in reduced wing tissue size caused by increased caspase-mediated apoptosis rather than decreased cell proliferation (wu2015pellemodulatesdfoxomediated pages 2-3). Pelle physically interacts with and phosphorylates dFoxO, promoting its cytoplasmic retention and preventing dFoxO-mediated transcription of pro-apoptotic genes (wu2015pellemodulatesdfoxomediated pages 2-3). When Pelle is depleted, dFoxO translocates to the nucleus, activates target genes including Thor/4E-BP, and triggers caspase activation and cell death (wu2015pellemodulatesdfoxomediated pages 2-3).
A groundbreaking 2024 study by Zhang et al. revealed a novel role for Pelle in maintaining neuronal autophagy and dopamine neuron survival (zhang2024maintainingtollsignaling pages 10-12, zhang2024maintainingtollsignaling pages 8-10, zhang2024maintainingtollsignaling pages 6-8, zhang2024maintainingtollsignaling pages 1-2). Toll-1 and Toll-7 signaling promote autophagy through a Tube-Pelle-PP2A signaling axis, with both Tube and Pelle being essential for Toll-induced autophagy in cultured cells (zhang2024maintainingtollsignaling pages 8-10, zhang2024maintainingtollsignaling pages 6-8). Knockdown of either Tube or Pelle blocked Toll-receptor-mediated autophagy, as evidenced by reduced LC3-II accumulation and increased P62 levels (zhang2024maintainingtollsignaling pages 6-8). The pathway appears to function by maintaining PP2A activity and regulating Akt-TOR signaling to sustain basal autophagy in dopamine neurons (zhang2024maintainingtollsignaling pages 10-12, zhang2024maintainingtollsignaling pages 8-10). Loss of Toll signaling components reduced TH-positive dopamine neuron numbers, increased neuronal cell death (detected by TUNEL staining), and impaired climbing ability, suggesting relevance to neurodegenerative processes (zhang2024maintainingtollsignaling pages 8-10, zhang2024maintainingtollsignaling pages 6-8).
Recent studies by Dillard et al. (2024 preprint, 2025 peer-reviewed publication) identified Pelle/IRAK as rate-limiting for tumor growth in a Drosophila RasV12; scrib-/- carcinoma model (dillard2024oncogenicrasdrivendorsalnfκb pages 5-8, dillard2025nfκbsignalingdriven pages 1-2, dillard2025nfκbsignalingdriven pages 2-5, dillard2024oncogenicrasdrivendorsalnfκb pages 1-5). Tumor-specific knockdown of pelle caused drastic reduction in tumor size, placing Pelle as a critical component of pro-tumorigenic Toll-NF-κB signaling (dillard2024oncogenicrasdrivendorsalnfκb pages 5-8, dillard2025nfκbsignalingdriven pages 1-2, dillard2025nfκbsignalingdriven pages 2-5). The study found that oncogenic Ras drives elevated Toll pathway activity and increased Dorsal expression, particularly in invasive tumor cell populations (dillard2025nfκbsignalingdriven pages 1-2, dillard2024oncogenicrasdrivendorsalnfκb pages 1-5). Mechanistically, Dorsal cooperates with the transcription factor Chinmo to promote malignancy by suppressing differentiation, counteracting apoptosis, and promoting invasion (dillard2025nfκbsignalingdriven pages 1-2, dillard2024oncogenicrasdrivendorsalnfκb pages 1-5). This work demonstrates that Pelle/IRAK is not merely an immune pathway component but also contributes to oncogenic signaling in epithelial tumors.
| Biological process/pathway | Pelle’s role | Key downstream events | Evidence and year |
|---|---|---|---|
| Toll–NF-κB innate immunity | Receptor-proximal serine/threonine kinase recruited through the MyD88–Tube–Pelle death-domain complex; directly phosphorylates signal-responsive sites in Cactus. | Slimb-dependent ubiquitination and proteasomal degradation of Cactus release Dif/Dorsal for nuclear entry and induction of Toll-responsive genes, including antimicrobial peptides. | Direct Cactus-kinase evidence, 2013; recent immunity synthesis, 2022 (daigneault2013theirakhomolog pages 2-3, valanne2011thedrosophilatoll pages 4-5, daigneault2013theirakhomolog pages 1-2, yu2022drosophilainnateimmunity pages 17-17) |
| Embryonic dorsoventral patterning | Transduces the spatially restricted maternal Toll signal after recruitment to membrane-proximal signaling sites and activation by autophosphorylation. | Graded Cactus degradation generates the ventral-to-dorsal nuclear Dorsal gradient, specifying mesodermal, neuroectodermal, and dorsal cell fates. | Genetic and complex-assembly evidence, 1999–2004; evolutionary/mechanistic synthesis, 2009 (sun2004regulatedassemblyof pages 1-2, govind1999controlofdevelopment pages 3-4, towb2009tubeisan pages 6-8, sun2004regulatedassemblyof pages 2-3) |
| Toll-complex assembly and feedback control | Its N-terminal death domain binds Tube, while its C-terminal kinase domain supplies catalytic output; recruited Pelle autophosphorylates and can phosphorylate Tube. | Dynamic assembly and possible phosphorylation-dependent disassembly or attenuation of the MyD88–Tube–Pelle complex regulate signal strength and duration. | Biochemical and assembly studies, 1999–2004; mechanistic synthesis, 2013 (daigneault2013theirakhomolog pages 3-5, schiffmann1999formationandbiochemical pages 2-3, sun2004regulatedassemblyof pages 9-9) |
| dFoxO-dependent cell survival and apoptosis | Physically interacts with and phosphorylates dFoxO in a function reported to be independent of canonical Toll signaling. | Pelle restrains dFoxO nuclear localization and pro-apoptotic transcription; pll depletion elevates Thor/4E-BP expression, caspase activity, and cell death, reducing wing cell number. | Direct genetic, interaction, and phosphorylation evidence, 2015 (wu2015pellemodulatesdfoxomediated pages 2-3) |
| Neuronal autophagy and dopamine-neuron maintenance | Required downstream of Toll-1 and Toll-7 in a Tube–Pelle–PP2A signaling axis; Toll-1 additionally requires dMyD88, whereas Toll-7-associated autophagy was dMyD88-independent. | Maintains PP2A activity and basal autophagy; pathway disruption increases P62 and ubiquitinated proteins, alters Akt–TOR signaling, reduces dopamine-neuron survival, and impairs climbing. | S2-cell knockdown and fly-brain evidence, 2024; direct Pelle requirement was strongest in cultured-cell autophagy assays (zhang2024maintainingtollsignaling pages 10-12, zhang2024maintainingtollsignaling pages 8-10, zhang2024maintainingtollsignaling pages 6-8, zhang2024maintainingtollsignaling pages 1-2) |
| Ras-driven epithelial tumorigenesis | Acts as a rate-limiting intracellular Toll–NF-κB signaling hub within RasV12; scrib tumor tissue. | Pelle knockdown drastically reduces tumor size; downstream Dorsal signaling supports growth and malignancy by opposing apoptosis, suppressing differentiation, and promoting invasion. | Drosophila carcinoma preprint, 2024; peer-reviewed confirmation, 2025 (dillard2024oncogenicrasdrivendorsalnfκb pages 5-8, dillard2025nfκbsignalingdriven pages 1-2, dillard2025nfκbsignalingdriven pages 2-5, dillard2024oncogenicrasdrivendorsalnfκb pages 1-5) |
| Wing development and tissue homeostasis | Preserves cell number by suppressing inappropriate dFoxO-dependent apoptosis rather than by increasing cell size or proliferation. | Loss of pll causes reduced wing tissue and anterior cross-vein defects through enhanced apoptotic signaling. | Genetic evidence, 2015 (wu2015pellemodulatesdfoxomediated pages 2-3) |
| Mesoderm and muscle development | Supplies the kinase output of strong embryonic Toll signaling required for ventral fate specification. | Nuclear Dorsal induces mesoderm; loss of Tube/Pelle signaling dorsalizes embryos and eliminates ventral mesodermal derivatives and normal muscle development. | Rescue and loss-of-function evidence summarized in 2009 (wu2015pellemodulatesdfoxomediated pages 24-25, towb2009tubeisan pages 6-8) |
| Neuronal development and axon targeting | Genetic studies implicate Pelle in photoreceptor axon targeting, although the immediate substrate and relationship to canonical Toll signaling remain incompletely defined. | Contributes to establishment of appropriate visual-system connectivity. | Developmental role summarized in 2015; mechanistic evidence remains limited (wu2015pellemodulatesdfoxomediated pages 24-25) |
Table: This table distinguishes Pelle’s established canonical Toll functions from newer or less completely resolved roles in cell survival, neuronal autophagy, and tumorigenesis. It also indicates the year and strength or scope of the supporting evidence.
Pelle is evolutionarily related to mammalian IRAK proteins within the broader RLK/Pelle kinase family (towb2009tubeisan pages 10-11, gosu2012molecularevolutionand pages 11-12, towb2009tubeisan pages 2-3, towb2009tubeisan pages 4-5). Phylogenetic analyses suggest that Pelle is most closely related to mammalian IRAK1, IRAK2, and IRAKM, sharing the non-RD kinase classification with these proteins (gosu2012molecularevolutionand pages 11-12, gosu2012molecularevolutionand pages 4-5, towb2009tubeisan pages 4-5). However, the evolutionary relationship is complex: while Pelle was historically considered the Drosophila homolog of mammalian IRAKs, comparative studies indicate that Tube (the Pelle-binding adaptor) is more specifically the homolog of IRAK-4, while Pelle corresponds functionally to IRAK-1 (towb2009tubeisan pages 10-11, gosu2012molecularevolutionand pages 1-2, towb2009tubeisan pages 2-3).
Functionally, Pelle serves as the Drosophila counterpart of IκB kinase (IKK) in Toll signaling, even though it is structurally an IRAK-family member rather than an IKK (daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 1-2). This functional equivalence reflects the evolutionary adaptation of the Toll pathway: in mammals, IRAK proteins activate IKK complexes, which then phosphorylate IκB; in Drosophila, Pelle directly phosphorylates Cactus/IκB, combining the IRAK and IKK functions in a single kinase (daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 1-2). The conserved architecture of death-domain-mediated assembly, MyD88 recruitment, and downstream NF-κB activation demonstrates the ancient origins of this innate immune signaling system (towb2009tubeisan pages 10-11, towb2009tubeisan pages 2-3, li2002irak4anovel pages 2-3).
Pelle activation occurs through a multi-step process initiated by Toll receptor engagement (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 2-3). Following Toll activation by processed Spätzle ligand, Toll recruits MyD88, which brings the preassembled MyD88-Tube complex to the receptor (sun2004regulatedassemblyof pages 2-3, sun2004regulatedassemblyof pages 1-2, sun2004regulatedassemblyof pages 8-9). Tube then recruits inactive Pelle through death-domain interactions (daigneault2013theirakhomolog pages 3-5, sun2004regulatedassemblyof pages 2-3). Within this assembled signaling complex, Pelle undergoes autoactivation through autophosphorylation (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 2-3, daigneault2013theirakhomolog pages 5-6). This autophosphorylation is evidenced by a slight decrease in electrophoretic mobility and can occur when recombinant Pelle is incubated at high concentration with Mg2+ and ATP (daigneault2013theirakhomolog pages 2-3). Importantly, Pelle activation does not require phosphorylation by an upstream kinase; rather, recruitment and assembly promote the autophosphorylation event (daigneault2013theirakhomolog pages 3-5, daigneault2013theirakhomolog pages 5-6). The activated state enables Pelle to efficiently phosphorylate downstream substrates, particularly Cactus (daigneault2013theirakhomolog pages 3-5).
Pelle kinase has emerged as a multifunctional signaling hub with roles extending well beyond its canonical function in Toll-mediated immunity. Recent 2024 studies have revealed unexpected functions in neuronal autophagy, dopamine neuron survival, and oncogenic tumorigenesis, expanding our understanding of IRAK-family kinase biology (zhang2024maintainingtollsignaling pages 10-12, zhang2024maintainingtollsignaling pages 8-10, dillard2024oncogenicrasdrivendorsalnfκb pages 5-8, dillard2025nfκbsignalingdriven pages 1-2). The conservation of Toll-IRAK signaling architecture from Drosophila to mammals, combined with the functional divergence of specific pathway components, makes Pelle an important model for understanding evolutionarily conserved innate immune and inflammatory mechanisms (towb2009tubeisan pages 10-11, towb2009tubeisan pages 2-3, schirato2016toll2signallingsafeguards pages 20-24).
Key open questions include the precise molecular mechanisms by which Pelle regulates PP2A activity in neurons, the structural determinants of Pelle substrate specificity beyond the established Cactus phosphorylation sites, and the potential therapeutic implications of targeting IRAK signaling in cancer and neurodegeneration. The demonstration that Pelle/IRAK is rate-limiting for tumor growth in Drosophila carcinoma models (dillard2025nfκbsignalingdriven pages 1-2, dillard2025nfκbsignalingdriven pages 2-5) suggests that mammalian IRAK proteins may represent viable therapeutic targets in oncology, a hypothesis that warrants further investigation in mammalian systems.
Pelle (pll, CG5974, Q05652) is a 501-amino acid serine/threonine-protein kinase in Drosophila melanogaster that functions as the central intracellular kinase in Toll signaling. The enzyme catalyzes phosphorylation of Cactus at Ser74, Ser78, and Ser116, promoting Cactus degradation and releasing NF-κB-family transcription factors for nuclear translocation. Pelle localizes to the cytoplasm and is recruited to membrane-proximal Toll signaling complexes through death-domain interactions with Tube and MyD88. Beyond its canonical roles in innate immunity and embryonic patterning, recent 2024 studies reveal Pelle functions in neuronal autophagy maintenance, dopamine neuron survival, and oncogenic tumor growth. As the Drosophila homolog of mammalian IRAK proteins, Pelle serves as an important model for understanding conserved innate immune signaling mechanisms and their roles in development, neurodegeneration, and cancer.
References
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