Involved in chilling tolerance. Interacts with GPA1/RGA1. In cold tolerant cultivars (AC Q7X7S8) Met-187 is replaced by Lys-187. This polymorphism is associated with divergence in chilling tolerance of rice cultivars. COLD1 confers adaptation of japonica rice to chilling and originated from the Chinese wild populations of Oryza rufipogon. Belongs to the Golgi pH regulator (TC 1.A.38) family.