Final answer:
In the context of nonmuscle motility unaffected by antibodies against myosin I and II, myosin V and myosin VI are likely candidates since they operate independently of the sarcomere structure and are involved in different cellular processes, such as organelle transport. The correct option is 2: Myosin V and myosin VI.
Step-by-step explanation:
The question asked is related to the motility forms that are likely unaffected by antibodies against both myosin I and myosin II. Myosin proteins are motor proteins known to interact with actin filaments and facilitate movement.
These proteins are a part of a superfamily that includes various myosin classes, each of which could potentially be involved in different types of cellular motility. Considering the myosin gene family is large and diverse, with many isoforms having unique functions, it is plausible that other myosins may be responsible for alternative forms of motility that do not rely on myosin I or II.
Myosin proteins, such as myosin V and VI (option 2), are known to differ in structure and function compared to myosin I and II. These other myosins can be involved in processes such as organelle transport and vesicle trafficking within cells, independent of the classic sarcomere structure involved in muscle contraction. Thus, they could continue to facilitate cellular movement even when the activity of myosin I and II is inhibited by antibodies.
The correct option in the context of this question, assuming the antibodies do not cross-react with other myosins, would be option 2: Myosin V and myosin VI.