Muniscins

[5] In addition to FCHO1, FCHO2 and Syp1,[6][7] SGIP1 is also included in the family because it contains the μ (mu) homology domain and is involved in CME, even though it does not contain the F-BAR domain[1][8] Muniscins are known as alternate cargo adaptors.

That is, they participate in selecting which cargo molecules are internalized via CME.

[5] Additionally, the structure of the dimer, with its concave face oriented toward the plasma membrane, is thought to help curve the membrane as the clathrin coated pit forms.

[5] The muniscins are early arriving proteins involved in CME.

[10] The μ homology domain of muniscins has been reported to have evolved from part of an ancient cargo adaptor protein complex named TSET.

Structure of Muniscin proteins [ 1 ] and a dimer [ 2 ] of FCHO proteins
Ribbon representation of BAR domains from two monomers of endophilin-A1 . [ 3 ]
The μ homology domain of muniscins evolved from TCUP