CALR, or calreticulin, is a protein that plays a crucial role in various cellular processes, including calcium storage and signaling. It is primarily found in the endoplasmic reticulum, where it helps in protein folding and quality control. Mutations in the CALR gene are associated with certain blood disorders, particularly myeloproliferative neoplasms, which are conditions that lead to the overproduction of blood cells. Research has shown that CALR mutations can affect the function of blood cells and contribute to disease progression. Understanding CALR's role in these conditions is important for developing targeted therapies and improving patient outcomes in diseases like myeloproliferative neoplasms.