CALML4 (calmodulin-like protein 4) is a light chain protein that functions as a component of the intermicrovillar adhesion complex (IMAC), playing a critical role in epithelial brush border organization. It serves as a light chain for myosin-7b (MYO7B) and is required for efficient targeting of IMAC to microvillar tips, thereby regulating microvilli organization and length 1. CALML4 also binds to myosin-7a, the motor protein mutated in Usher syndrome type 1 (deaf-blindness), suggesting broader implications for hereditary sensory disorders 12. Unlike calmodulin, CALML4 is calcium-insensitive but remains critical for fine-tuning myosin mechanical properties 2. Beyond its canonical roles in cellular adhesion, CALML4 has emerged as a biomarker in multiple disease contexts. It is upregulated in osteoarthritis synovial tissue and serves as a diagnostic feature gene in machine learning models for OA detection 3. CALML4 is also elevated in H. pylori-related gastric cancer and associated with improved patient prognosis 4. Additionally, CALML4 correlates with neutrophil infiltration in pelvic inflammatory disease 5 and functions as a hub gene in acute myocardial infarction pathways 6. These findings suggest CALML4 has context-dependent roles extending beyond structural functions in microvilli organization.