Modulators of melanocortin receptors (MCR) are provided herein. An MC5R peptide ligand is represented by to Formula 1:

R.sub.1-Nle.sup.4-c[Xaa.sup.5-Yaa.sup.6-(NMe)D-Nal(2).sup.7-Arg.sup.8-Trp.sup.9-(NMe)Zaa.sup.10]-R.sub.2.

R.sub.1 can be an acetyl, a glycosylated amino acid, CO(CH.sub.2).sub.nCH.sub.3, or CO(CH.sub.2).sub.nCF.sub.3 with n ranging from 1 to 6. R.sub.2 can be an CONH.sub.2, COOH, or CH.sub.2OH. Xaa, Yaa, and Zaa can each be a natural amino acid or an unnatural amino acid.

The present invention relates to protein nanocages comprising a melanocyte-targeting moiety and pharmaceutical compositions comprising the protein cages as well as methods for treating or diagnosing hyperpigmentation disorders or other melanocyte-related disorders using the protein nanocages or pharmaceutical compositions.

The present invention relates to protein nanocages comprising a melanocyte-targeting moiety and pharmaceutical compositions comprising the protein cages as well as methods for treating or diagnosing hyperpigmentation disorders or other melanocyte-related disorders using the protein nanocages or pharmaceutical compositions.