Abstract: Provided herein are methods for increasing insulin sensitivity in a subject. A method may comprise administering to a subject in need of increased insulin sensitivity a therapeutically effective amount of a glypican-4 agent. Also provided herein are methods for determining whether a subject is or is likely to become insulin resistant. A method may comprise determining the level of glypican-4 in a subject, wherein an elevated level of glypican-4 indicates that a subject is or is likely to become insulin resistant.

Abstract: The present invention is based in part on the discovery of brown and white fat cell specific surface markers. It has been found that the small amino acid transporter Slca10/Asc1 is a specific surface marker for white adipocytes and that the ligand-gated ion channel P2X5 and the small amino acid transporter Slc36a2 are specific surface markers for brown adipocytes. Having identified these specific white and brown cell surface markers, the present invention provides compositions and methods suitable for the targeting of any number of agents to a white or brown adipose tissue and the identification and isolation of white or brown adipocytes for any number of uses including therapeutic, screening and diagnostic purposes.

Abstract: Provided herein are methods for increasing insulin sensitivity in a subject. A method may comprise administering to a subject in need of increased insulin sensitivity a therapeutically effective amount of a glypican-4 agent. Also provided herein are methods for determining whether a subject is or is likely to become insulin resistant. A method may comprise determining the level of glypican-4 in a subject, wherein an elevated level of glypican-4 indicates that a subject is or is likely to become insulin resistant.