{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nCalcium‐ and integrin‐binding protein 1 (CIB1) was initially uncovered as a key regulator of cardiomyocyte hypertrophy. By anchoring calcineurin to the sarcolemmal membrane in close association with L‐type Ca²⁺ channels, CIB1 modulates calcineurin activation and thus contributes to pathological, pressure overload-induced cardiac hypertrophy, whereas physiological hypertrophy remains largely unaffected."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its role in the heart, CIB1 acts as a negative regulator of kinase activity. For example, it can suppress the activity of the serum-inducible kinase Snk, thereby influencing cell morphology and potentially other signaling cascades that are initiated during early G₁ of the cell cycle."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nCIB1 also plays important roles in cell cycle regulation and differentiation. In vivo, its deletion leads to impaired spermatogenesis, reduced testis size, increased germ cell apoptosis, and delayed growth of embryonic fibroblasts, underscoring its involvement in the proper progression of the cell cycle and germ cell maturation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurthermore, CIB1 is essential in the regulation of platelet integrin signaling. By interacting with the platelet integrin αIIb, it participates in the modulation of inside-out and outside-in signaling events that are critical for platelet aggregation and proper hemostasis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn the vasculature, CIB1 functions to regulate angiogenesis. Loss of CIB1 in endothelial cells impairs migration, proliferation, and tubule formation, while also diminishing the activation of p21-activated kinase 1 and downstream signaling (such as ERK1/2 activation), ultimately resulting in reduced pathological and adaptive angiogenic responses in ischemic conditions."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn relation to neurodegeneration, CIB1 has been shown to influence amyloid β peptide production in Alzheimer’s disease models. By interacting with the γ‑secretase complex and specifically modulating the cell-surface localization of mature Nicastrin, CIB1 appears to act as a negative regulator of Aβ generation, hinting at its involvement in AD pathogenesis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nCIB1 also affords neuroprotection in models of Parkinson’s disease. It associates with apoptosis signal-regulating kinase 1 (ASK1) and, by impeding ASK1-mediated signaling, reduces dopaminergic neuron death in response to toxic insults."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nWhile a separate study underscored the role of integrin‐associated signaling in cellular contexts—the activation of c-Src linked to integrin β₃, for instance—these observations contribute to the broader understanding of how CIB1 may be intertwined with integrin-mediated outside-in signaling processes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nCIB1’s interaction network extends into the realm of immunoglobulin gene diversification. Although it was identified as a binding partner of activation-induced deaminase (AID), functional assays in knockout systems revealed that CIB1 is not critical for processes such as somatic hypermutation, gene conversion, or class switch recombination, suggesting a modulatory or redundant role in these events."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn megakaryocyte differentiation, CIB1 contributes to the regulation of endomitosis—a modified mitotic process that produces polyploid megakaryocytes. Overexpression of CIB1 in megakaryoblastic cells leads to altered cytokinesis dynamics and increased integrin αIIbβ₃ surface expression, an effect that appears to be mediated through augmented interaction with Polo-like kinase 3."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nRecent studies have further revealed that CIB1 functions within a multiprotein complex involving TMC6 and TMC8 in lymphocytes. Within this trimolecular complex, CIB1 acts to stabilize TMC6 and TMC8 proteins by preventing their ubiquitination and subsequent proteasomal degradation. These interactions provide insights into the pathogenesis of epidermodysplasia verruciformis, where mutations in any one of these proteins result in similar clinical phenotypes, and point to potential lymphocyte-driven mechanisms underlying the disease."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "11"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nLastly, studies utilizing a comprehensive mouse erythrocyte protein library have identified homologous calcium-binding proteins—related in function to CIB1—as interacting partners of the Plasmodium yoelii RhopH complex. These findings highlight the broad relevance of calcium-binding regulators in mediating critical host-pathogen interactions during malaria infection."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "12"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Joerg Heineke, Mannix Auger-Messier, Robert N Correll, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "The serum-inducible protein kinase Snk is a G1 phase polo-like kinase that is inhibited by the calcium- and integrin-binding protein CIB."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cancer Res (2003)"}]}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12651910"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12651910"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Weiping Yuan, Tina M Leisner, Andrew W McFadden, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CIB1 is essential for mouse spermatogenesis."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell Biol (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1128/MCB.01488-06"}], "href": "https://doi.org/10.1128/MCB.01488-06"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16982698"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16982698"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "M U Naik, A Nigam, P Manrai, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "CIB1 protects against MPTP-induced neurotoxicity through inhibiting ASK1."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-017-12379-3"}], "href": "https://doi.org/10.1038/s41598-017-12379-3"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28939911"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28939911"}]}, {"type": "r", "ref": 8, "children": [{"type": "t", "text": "Meghna U Naik, Tejal U Naik, Ross Summer, et al. 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