Which protein is produced by renal tubular epithelial cells?

The protein produced by renal tubular epithelial cells is Tamm-Horsfall protein, also known as uromodulin. This protein is secreted by the cells lining the nephron's ascending limb of the loop of Henle and is the most abundant protein in normal urine. Tamm-Horsfall protein plays a critical role in kidney function and urine formation by contributing to the formation of urinary casts and by helping to prevent urinary tract infections. Additionally, it may help in maintaining the osmolarity of urine and has potential protective functions against kidney injury.

In contrast, Bence Jones proteins are light chains of immunoglobulins produced by malignant plasma cells, and they are typically associated with multiple myeloma. Glomerular protein refers to proteins that pass through the glomerular filtration barrier, such as albumin, which primarily originates from plasma rather than being produced by renal tubular cells. Albumin itself is synthesized by the liver and acts as a marker for various kidney conditions when present in urine, but it is not produced by renal tubular epithelial cells. Thus, Tamm-Horsfall protein is specifically recognized as the protein that fulfills the criterion stated in the question.