Plays a role in influencing the retrograde trafficking of lysosomal sorting receptors SORT1 and IGF2R from the endosomes to the trans-Golgi network by controlling the recruitment of retromer complex to the endosomal membrane. Regulates the localization and activation of RAB7A which is required to recruit the retromer complex to the endosomal membrane. Interacts with SORT1, RAB5A and RAB7A. Interacts with PPT1, TPP1, CLN3, CLN6, CLN8, ATP5F1A and ATP5F1B. An amphipathic anchor region facilitates its association with the membrane. N-glycosylated with both high mannose and complex type sugars. Glycosylation is important for proper folding and trafficking to the lysosomes. The type II membrane signal anchor is proteolytically cleaved to produce a mature form that is transported to the lysosomes (Ceroid-lipofuscinosis neuronal protein 5, secreted form). Can undergo proteolytic cleavage at the C-terminus, probably by a cysteine protease and may involve the removal of approximately 10-15 residues from the C-terminal end. Defects in CLN5 are the cause of neuronal ceroid lipofuscinosis (NCL). NCL is characterized by brain atrophy and the accumulation of lysosome derived fluorescent storage bodies in neurons and most other cells. NCL is found in New Zealand Borderdale sheep. Belongs to the CLN5 family.