Understanding kidney injury molecule 1: a novel immune factor in kidney pathophysiology.

ABSTRACT

Kidney injury molecule 1 (KIM-1) is a type I membrane protein, comprising an extracellular portion and a cytoplasmic portion. It is also named as HAVCR1 (Hepatitis A virus cellular receptor 1) or TIM1 (T-cell immunoglobulin mucin receptor 1), and is expressed in the kidney, liver, and spleen. KIM-1 plays different roles via various molecular targets in immune diseases and kidney injury. KIM-1 is involved in HAV infections, autoimmunity, immune tolerance, and atopic diseases. The urinary KIM-1 level is closely related to its tissue level, and correspondingly related to kidney tissue damage. KIM-1 is not only an early biomarker of acute kidney injury (AKI), but also has a potential role in predicting the long-term renal outcome. In this review, we provide a summary of KIM-1's activities, focusing on the latest studies concerning the important roles of KIM-1 in the immune system and kidney diseases.