{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n ASB9 is a member of the ankyrin repeat and SOCS‐box protein family that functions as a substrate‐recognition subunit within ECS‐type Cullin RING E3 ubiquitin ligase complexes. In several studies, ASB9 was shown to bind specific creatine kinase isoforms via its ankyrin repeat domain and, through its SOCS box, promote their polyubiquitination and subsequent proteasomal degradation."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "4"}]}, {"type": "t", "text": " In doing so, ASB9 helps regulate intracellular levels of enzymes such as brain‐type and ubiquitous creatine kinase, thereby impacting cellular energy metabolism and other processes.\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Structural studies have demonstrated that, although intrinsically unstable alone, ASB9 forms a stable ternary complex with the Elongin B/C adapter proteins, which then binds with high affinity to the Cullin 5 N‐terminal domain. This assembly into a functional CRL complex underpins its role as a critical mediator of substrate ubiquitination."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Biological investigations in cancer contexts further indicate that ASB9 expression can be clinically important. In hepatocellular carcinoma, for instance, overexpression of ASB9 leads to reduced levels of creatine kinase, whereas lower ASB9 expression is associated with increased creatine kinase abundance and with more aggressive tumor behavior."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Similarly, studies in colorectal cancer have revealed that decreased ASB9 expression correlates with enhanced cell invasiveness and poor overall survival, making ASB9 a promising prognostic marker."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, in ovarian granulosa cells, ASB9 is dramatically induced in response to ovulatory signals (e.g., following hCG injection), and its inhibition leads to increased cell proliferation and modulation of MAPK signaling. These data suggest that ASB9 plays an important role in folliculogenesis by targeting select proteins for degradation, thereby contributing to the proper transition from proliferation to differentiation in the periovulatory period."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In summary, ASB9 acts as a specialized substrate receptor that facilitates the ubiquitin‐mediated degradation of key proteins such as creatine kinase isoforms. Through its participation in CRL complexes, ASB9 influences cellular energy homeostasis, tumor behavior, and reproductive cell differentiation, highlighting its multifaceted roles in both normal physiology and disease.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Marlyse A Debrincat, Jian-Guo Zhang, Tracy A Willson, et al. 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