IQ motif-containing protein J (IQCJ)

IQ motif-containing protein J (IQCJ) is a protein characterized by the presence of the IQ motif, a sequence of approximately 25 amino acids conforming to the consensus [I,L,V]QxxxRGxxx[R,K] that forms a seven-turn α-helix capable of binding *calmodulin* in a Ca²⁺-independent manner[1][5]. The IQ motif is a calmodulin-binding domain, and proteins featuring this motif often interact with calmodulin to mediate Ca²⁺-dependent and -independent signaling within the cell. Multiple IQ domain-containing proteins have diverse cellular roles, often related to cytoskeletal organization and signal transduction. Although IQCJ's exact biological roles remain poorly defined, its family is structurally associated with proteins involved in cellular signaling and organization. There is currently no published evidence directly implicating IQCJ as a therapeutic target or in specific diseases, and no drugs or clinical biomarkers are reported to interact with it[1][5]. Notes: - IQCJ should not be confused with IQGAP proteins, which are better-studied calmodulin interactors with more defined signaling and cytoskeletal functions[2][3]. - IQCJ is defined by its calmodulin-binding IQ domain but does not appear in major therapeutic target listings, nor are there published data supporting its role in human disease or therapeutics.

Other names

IQCJIQ domain-containing protein Jcalmodulin binding protein