Some elements exist naturally as molecules. For example, hydrogen and oxygen exist as two-atom molecules.

TLS Online TPP Program

#Id: 10008

#XL - T Zoology

The freed C-terminal is not involved in signaling and is often degraded, whereas the N-terminal becomes the active Hedgehog protein intended for secretion

TLS Online TPP Program

#Id: 10009

#XL - T Zoology

Secretion requires the addition of cholesterol and palmitic acid to the Hedgehog protein

TLS Online TPP Program

#Id: 10010

#XL - T Zoology

Two membrane proteins, 

Smoothened (Smo) 

Patched (Ptc)

TLS Online TPP Program

#Id: 10011

#XL - T Zoology

Smo has seven TM α helices, is a member of the GPCR superfamily, and is related in sequence to the Fz.

TLS Online TPP Program

#Id: 10012

#XL - T Zoology

Ptc contains 12 TM α helices and structurally similar

to the Niemann-Pick C1 protein, a cholesterol transporting member of the ABC superfamily

TLS Online TPP Program

#Id: 10013

#XL - T Zoology

In the absence of Hh,

Ptc inhibits Smoothened and then degraded in proteasomes