1. Homology
    Orthologs  Paralogs 

2. Gene
    Expression 

3. Protein
    Structure  Predicted Function 

4. References

Homology

Orthologs

Sequenced distant orthologs of human PTCHD4 have been found as far back in evolution as mold, which shows a conservation of 16% identity.^[3] Strict orthologs include boneless fish, but not echinoderms, insects, or plants.

(ORTHOLOG TABLE IMAGE)

Figure 1: Table of example orthologs

(SCATTER PLOT IMAGE)

Figure 2: Scatter plot of conservation with human PTCHD4 versus date of divergence in millions of years ago

Paralogs

PTCHD4 has three other genes in its family: PTCHD1, PTCHD2, and PTCHD3, as well as the Niemann-Pick disease type C protein.^[4] These paralogs are far less conserved than strict orthologs, which may suggest that they split long before speciation.^[4]

Gene

Human PTCHD4 is located on the negative strand of chromosome 6, at 6p12.3.^[1] From there, it covers 190,350 base pairs, which includes three exons and two introns.

(LOCATION IMAGE)

Figure 3, which shows the location of gene PTCHD4 on chromosome 6, is courtesy of GeneCards.org.

Expression

Nominal expression of PTCHD4 was found in the brain, connective tissue, embryonic tissue, lungs, placenta, testis, trachea, and uterus, with the greatest expression in the trachea.^[5] Nominal expression was also found in the following disease states: chondrosarcoma, germ cell tumors, non-neoplasia, and uterine tumors. Protein localization was found in all tissues examined except the salivary glands, yet RNA expression was scarcely found anywhere.^[6] This may suggest that PTCHD4 protein is particularly resilient to degradation, and that it is only produced under key circumstances or at key life stages.

Protein

Structure

Phyre2 extrapolated the following 3D secondary structure with 100% certainty after analyzing 745 residues, (an 88% majority) of PTCHD4’s human protein sequence.^[8] Results were remarkably similar in such distant orthologs as earthworms, boneless fish, and green algae. There are an estimate 10 transmembrane helices.^[7]

(STRUCTURE)

Predicted Function

PTCHD4 has been implicated as an integral component of cellular membrane,^[9] and as a protein receptor in the hedgehog pathway. The later of these two functions causes an inhibitory effect during the development of embryonic cells in all bilaterians and vertebrates.^[10] In mammals, the hedgehog pathway is vital to the proper development of the brain, skeleton, musculature, gastrointestinal tract, and lungs. It also appears to be important to adult animals, as it has been implicated in the regulation of adult stem cells, while its malfunction is associated basal cell carcinoma.^[11]

References

• Ernest William Castine
• Ernest William Freeland
• Ernest William Hawkes
• Ernest William Hornung
• Ernest William Hornung bibliography
• Ernest William MacBride
• Ernest William Radford
• Ernest William Richardson
• Ernest William Roberts (rugby footballer)
• Ernest Williams (conductor)
• Ernest William Southcott
• Ernest William Tristram
• Ernest William Turner
• Ernest Willoughby Petter
• Ernest Wills (coach)
• Ernest Wills (disambiguation)
• Ernest Wilson (murder victim)
• Ernest W. Lewis
• Ernest W. Maglischo
• Ernest Wollan
• Ernest Wong
• Ernest Wood (Manitoba politician)
• Ernest Worrall
• Ernest Wright Alexander
• Ernest Wright (English cricketer)