Q. When citing APA, do I capitalize proper nouns in the title?

According to the OWL:

If you refer to the title of a source within your paper, capitalize all words that are four letters long or greater within the title of a source: Permanence and Change. Exceptions apply to short words that are verbs, nouns, pronouns, adjectives, and adverbs: Writing New Media, There Is Nothing Left to Lose.

(Note: in your References list, only the first word of a title will be capitalized: Writing new media.)

Use a capital letter for the first word in a subtitle, too.

Let me know if you still have questions.