HSPG2 and Obesity: In addition, the secretion of axon guidance-related proteins, namely, perlecan (Hspg2), dickkopf-like protein 1 (Dkkl1), cathepsin B (Ctsb), matrilin-4 (Matn4), and nidogen-1 (Nid1), were induced collectively in the secretome of SIK2-depleted cells in response to early ER stress induction, and similar to SIK2 overexpression in feeding and obesity-related group, SIK2 overexpression increased the secretion of these proteins in a stress-independent manner, except for Dkkl1.