S100A11 also known as Calgizzarin is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100A11 is a calcium-binding protein characterized by two EF-hand motifs, which are crucial for regulating intracellular calcium levels. This regulation is vital for numerous cellular processes, including muscle contraction, cell growth, and signal transduction pathways. Expression of S100A11 is predominantly found in lung tissue, but also present in kidney, liver, brain, heart, and smooth muscle, highlighting diverse roles in various tissues. S100A11 is an androgen-responsive protein produced by Sertoli cells, suggesting involvement in spermatogenesis regulation, which is essential for male fertility.